Error while linking libxml2 - c

I have a simple example for libxml2 but it returns the following error:
$ gcc -Wall -lxml2 -I/usr/include/libxml2 -o ex1 ex1.c
/tmp/cc6OKSKJ.o: In function `main':
ex1.c:(.text+0x60): undefined reference to `xmlReadFile'
ex1.c:(.text+0x70): undefined reference to `xmlDocGetRootElement'
collect2: ld returned 1 exit status
$ xml2-config --libs
-lxml2
$ xml2-config --cflags
-I/usr/include/libxml2
I'm on Lubuntu 11.10 x86_64 and I have all the packages I need (well I think): libxml2, libxml2-dev, libxml2-dbg... Here's the code of the example:
// gcc -Wall -lxml2 -I/usr/include/libxml2 -o ex1 ex1.c
#include <stdio.h>
#include <string.h>
#include <libxml/parser.h>
int main(int argc, char **argv)
{
xmlDoc *document;
xmlNode *root, *first_child, *node;
char *filename;
if (argc < 2)
{
fprintf(stderr, "Usage: %s filename.xml\n", argv[0]);
return 1;
}
filename = argv[1];
document = xmlReadFile(filename, NULL, 0);
root = xmlDocGetRootElement(document);
fprintf(stdout, "Root is <%s> (%i)\n", root->name, root->type);
first_child = root->children;
for (node = first_child; node; node = node->next)
{
fprintf(stdout, "\t Child is <%s> (%i)\n", node->name, node->type);
}
fprintf(stdout, "...\n");
return 0;
}

Your link line is incorrect. Try
gcc -Wall -I/usr/include/libxml2 -o ex1 ex1.c -lxml2
Read this to understand why the order of sources and libraries on command line matters.

Related

ppu-ld cannot find -lspe

I am trying to compile the code below, on CELL BE Simulator(mambo).
//hello.c
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <libspe.h>
#include <sched.h>
extern spe_program_handle_t hello_spu;
spe_gid_t gid;
speid_t speids[8];
int status[8];
int main(int argc, char *argv[]){
int i;
printf("Hello World!\n");
gid = spe_create_group (SCHED_OTHER, 0, 1);
if (gid == NULL) {
fprintf(stderr, "Failed spe_create_group(errno=%d)\n", errno);
return -1;
}
if (spe_group_max (gid) < 8) {
fprintf(stderr, "System doesn't have eight working SPEs. I'm leaving.\n");
return -1;
}
for (i = 0; i < 8; i++) {
speids[i] = spe_create_thread (gid, &hello_spu,NULL, NULL, -1, 0);
if (speids[i] == NULL) {
fprintf (stderr, "FAILED: spe_create_thread(num=%d, errno=%d)\n",i, errno);
exit (3+i);
}
}
for (i=0; i<8; ++i){
spe_wait(speids[i], &status[i], 0);
}
__asm__ __volatile__ ("sync" : : : "memory");
return 0;
}
//Makefile
########################################################################
# Target
########################################################################
PROGRAM_ppu64 = hello
########################################################################
# Local Defines
########################################################################
IMPORTS = ../spu/hello_spu.a -lspe
########################################################################
# make.footer
########################################################################
include /opt/cell/sdk/buildutils/make.footer
After compiling the this, it provides with the following output.
$make
/opt/cell/toolchain/bin/ppu-gcc -W -Wall -Winline -I. -I /opt/cell/sysroot usr/include -I /opt/cell/sysroot/opt/cell/sdk/usr/include -mabi=altivec -maltivec -O3 -c
hello.c
hello.c: In function 'main':
hello.c:12: warning: unused parameter 'argc'
hello.c:12: warning: unused parameter 'argv'
/opt/cell/toolchain/bin/ppu-gcc -o hello hello.o -L/opt/cell/sysroot/usr/lib64 -L/opt/cell/sysroot/opt/cell/sdk/usr/lib64 -R/opt/cell/sdk/usr/lib64 ../spu/hello_spu.a -lspe
/opt/cell/toolchain/bin/ppu-ld: cannot find -lspe
collect2: ld returned 1 exit status
make: *** [hello] Error 1
'ld' cannot find the -lspe library.The "/opt/cell/sysroot/usr/lib" directory contains following libraries and files,
alf, libblas.so, libc_stubs.a, libieee.a, libnetpbm.so.10, libnuma.so.1, libsimdmath.so.3,
crt1.o, libblas.so.1, libdl.a, libm.a, libnetpbm.so.10.35, libpthread.a, libsimdmath.so.3.0.3,
crti.o, libBrokenLocale.a, libdl.so, libmass.a, libnldbl_nonshared.a, libpthread_nonshared.a, libspe2.so,
crtn.o, libBrokenLocale.so, libg.a, libmassv.a, libnsl.a, libpthread.so, libspe2.so.2,
gconv, libbsd.a, libgmp.a, libmcheck.a, libnsl.so, libresolv.a, libspe2.so.2.2.0,
gcrt1.o, libbsd-compat.a, libgmp.so, libmp.a, libnss_compat.so, libresolv.so, libthread_db.so,
libalf.a, libc.a, libgmp.so.3, libmpfr.a, libnss_dns.so, librpcsvc.a, libutil.a,
libalf.so, libcidn.so, libgmp.so.3.3.3, libmp.so, libnss_files.so, librt.a, libutil.so,
libalf.so.3, libc_nonshared.a, libgmpxx.a, libmp.so.3, libnss_hesiod.so, librtkaio.a, Mcrt1.o,
libalf.so.3.0.0, libcrypt.a, libgmpxx.so, libmp.so.3.1.7, libnss_nisplus.so, librt.so, Scrt1.o,
libanl.a, libcrypt.so, libgmpxx.so.3, libm.so, libnss_nis.so, libsimdmath.a,
libanl.so, libc.so, libgmpxx.so.3.0.5, libnetpbm.so, libnuma.so, libsimdmath.so
How do I link libspe2.so to libspe.so?
Please, help.
You don't link those together. They are different things. You either update your makefile to use -lspe2 if that's the version of the library you want or you install the version of the library that installs the libspe.so library.

combine fuse and rpc for remote directory listing

I'm developing a custom file system with fuse. What I want to do is to read contents of a directory from remote server and list them in mount point. My rpc program run solely well. but when I try to combine it with rpc it got some build error. I'm using rpcgen to create my rpc program but I don't know how exactly I should build them together.
this is my cfs_client.c :
/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2007 Miklos Szeredi <miklos#szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
gcc -Wall cfs.c `pkg-config fuse --cflags --libs` -o cfs
*/
#define FUSE_USE_VERSION 26
#include <fuse.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include "cfs.h"
static const char *cfs_str = "Hello World!\n";
static const char *cfs_path = "/cfs";
static int cfs_getattr(const char *path, struct stat *stbuf) {
int res = 0;
memset(stbuf, 0, sizeof (struct stat));
if (strcmp(path, "/") == 0) {
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
} else if (strcmp(path, cfs_path) == 0) {
stbuf->st_mode = S_IFREG | 0444;
stbuf->st_nlink = 1;
stbuf->st_size = strlen(cfs_str);
} else
res = -ENOENT;
return res;
}
static int cfs_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
off_t offset, struct fuse_file_info *fi) {
(void) offset;
(void) fi;
char *host = "localhost";
char *dirname = "/home/hamed/test";
CLIENT *clnt;
readdir_res *result_1;
if (strcmp(path, "/") != 0)
return -ENOENT;
#ifndef DEBUG
clnt = clnt_create(host, CFSPROG, CFSVERS, "udp");
if (clnt == NULL) {
clnt_pcreateerror(host);
exit(1);
}
#endif /* DEBUG */
result_1 = readdir_1(&dirname, clnt);
if (result_1 == (readdir_res *) NULL) {
clnt_perror(clnt, "call failed");
}
namelist nl;
nl = result_1->readdir_res_u.list;
while (nl) {
printf("dirname = %s\n", nl->name);
filler(buf, nl->name, NULL, 0);
nl = nl->next;
}
#ifndef DEBUG
clnt_destroy(clnt);
#endif /* DEBUG */
return 0;
}
static int cfs_open(const char *path, struct fuse_file_info *fi) {
if (strcmp(path, cfs_path) != 0)
return -ENOENT;
if ((fi->flags & 3) != O_RDONLY)
return -EACCES;
return 0;
}
static int cfs_read(const char *path, char *buf, size_t size, off_t offset,
struct fuse_file_info *fi) {
size_t len;
(void) fi;
if (strcmp(path, cfs_path) != 0)
return -ENOENT;
len = strlen(cfs_str);
if (offset < len) {
if (offset + size > len)
size = len - offset;
memcpy(buf, cfs_str + offset, size);
} else
size = 0;
return size;
}
static struct fuse_operations cfs_oper = {
.getattr = cfs_getattr,
.readdir = cfs_readdir,
.open = cfs_open,
.read = cfs_read,
};
int main(int argc, char *argv[]) {
return fuse_main(argc, argv, &cfs_oper, NULL);
}
here is my cfs_server.c :
/*
* This is sample code generated by rpcgen.
* These are only templates and you can use them
* as a guideline for developing your own functions.
*/
#include "cfs.h"
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <rpc/pmap_clnt.h>
readdir_res * readdir_1_svc(nametype *dirname, struct svc_req *rqstp) {
DIR *dp;
struct dirent *directory;
static readdir_res result;
int inode;
namelist nl;
namelist *nlp;
dp = opendir(*dirname);
if (dp != NULL) {
nlp = &result.readdir_res_u.list;
while (directory = readdir(dp)) {
nl = *nlp = (namenode *) malloc(sizeof (namenode));
nl->name = directory->d_name;
nlp = &nl->next;
}
}
*nlp = NULL;
result.errnum = 0;
closedir(dp);
return &result;
}
and this is make file that I useed :
# This is a template Makefile generated by rpcgen
# Parameters
CLIENT = cfs_client
SERVER = cfs_server
SOURCES_CLNT.c =
SOURCES_CLNT.h =
SOURCES_SVC.c =
SOURCES_SVC.h =
SOURCES.x = cfs.x
TARGETS_SVC.c = cfs_svc.c cfs_server.c cfs_xdr.c
TARGETS_CLNT.c = cfs_clnt.c cfs_client.c cfs_xdr.c
TARGETS = cfs.h cfs_xdr.c cfs_clnt.c cfs_svc.c cfs_client.c cfs_server.c
OBJECTS_CLNT = $(SOURCES_CLNT.c:%.c=%.o) $(TARGETS_CLNT.c:%.c=%.o)
OBJECTS_SVC = $(SOURCES_SVC.c:%.c=%.o) $(TARGETS_SVC.c:%.c=%.o)
# Compiler flags
CFLAGS += -g -Wall -DRPC_SVC_FG $(shell pkg-config fuse --cflags --libs)
LDLIBS += -lnsl
RPCGENFLAGS = -g
# Targets
all : $(CLIENT) $(SERVER)
$(TARGETS) : $(SOURCES.x)
rpcgen $(RPCGENFLAGS) $(SOURCES.x)
$(OBJECTS_CLNT) : $(SOURCES_CLNT.c) $(SOURCES_CLNT.h) $(TARGETS_CLNT.c)
$(OBJECTS_SVC) : $(SOURCES_SVC.c) $(SOURCES_SVC.h) $(TARGETS_SVC.c)
$(CLIENT) : $(OBJECTS_CLNT)
$(LINK.c) -o $(CLIENT) $(OBJECTS_CLNT) $(LDLIBS)
$(SERVER) : $(OBJECTS_SVC)
$(LINK.c) -o $(SERVER) $(OBJECTS_SVC) $(LDLIBS)
clean:
$(RM) core $(TARGETS) $(OBJECTS_CLNT) $(OBJECTS_SVC) $(CLIENT) $(SERVER)
edit :
error is :
root#debian:/programs/c/rpc/custom file system# make -f Makefile.cfs
rpcgen -g cfs.x
usage: rpcgen infile
rpcgen [-abkCLNTM][-Dname[=value]] [-i size] [-I [-K seconds]] [-Y path] infile
rpcgen [-c | -h | -l | -m | -t | -Sc | -Ss | -Sm] [-o outfile] [infile]
rpcgen [-s nettype]* [-o outfile] [infile]
rpcgen [-n netid]* [-o outfile] [infile]
options:
-a generate all files, including samples
-b backward compatibility mode (generates code for SunOS 4.1)
-c generate XDR routines
-C ANSI C mode
-Dname[=value] define a symbol (same as #define)
-h generate header file
-i size size at which to start generating inline code
-I generate code for inetd support in server (for SunOS 4.1)
-K seconds server exits after K seconds of inactivity
-l generate client side stubs
-L server errors will be printed to syslog
-m generate server side stubs
-M generate MT-safe code
-n netid generate server code that supports named netid
-N supports multiple arguments and call-by-value
-o outfile name of the output file
-s nettype generate server code that supports named nettype
-Sc generate sample client code that uses remote procedures
-Ss generate sample server code that defines remote procedures
-Sm generate makefile template
-t generate RPC dispatch table
-T generate code to support RPC dispatch tables
-Y path directory name to find C preprocessor (cpp)
For bug reporting instructions, please see:
<http://www.debian.org/Bugs/>.
make: *** [cfs_clnt.c] Error 1
I've solved my problem by using a bash file. This is my script for those who may have same problem as mine :
cc -g -c -o cfs_clnt.o cfs_clnt.c
cc -g -D_FILE_OFFSET_BITS=64 -c -o cfs_client.o cfs_client.c
cc -g -c -o cfs_xdr.o cfs_xdr.c
cc -g -o cfs_client cfs_clnt.o cfs_client.o cfs_xdr.o -lnsl -Wall `pkg-config fuse --cflags --libs`
cc -g -c -o cfs_svc.o cfs_svc.c
cc -g -c -o cfs_server.o cfs_server.c
cc -g -o cfs_server cfs_svc.o cfs_server.o cfs_xdr.o -lnsl

Error while including header file using make

I have to compile two independent processes-sendfdsock.c and recvfdsock.c using make file. Both the files have there own main function. This means they are independent and I have to compile them as two different binaries. This is my make file:
compileAll:sendfdsock recvfdsock
sendfdsock:sendfdsock.o
gcc -o sendfdsock sendfdsock.o
sendfdsock.o:sendfdsock.c accessories.h
gcc -c sendfdsock.c
recvfdsock.o:recvfdsock.c accessories.h
gcc -c recvfdsock.c
recvfdsock:recvfdsock.o
gcc -o recvfdsock recvfdsock.o
Here I have made a compileAll target which compiles both the files.
Both files need to use accessories.h. As mention in GNU Make Doc - A simple Make file. I wrote this make file.
accessories.h :
#include <malloc.h>
#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <error.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/un.h>
#include <stropts.h>
#define PORT "4444" //port we are listening on
int sendall(int fd, char *buf, int *len);
int recvall(int fd, char *buf, int *len);
void logp(int typ, char* msg);
void errorp(char *where, int boolean, int errn,char *what);
accessories.c :
#include "accessories.h"
void logp(int typ, char* msg) // typ --> type(category) of message [1-Normal Log, 2-Warning(any unexpected thing happened), 3-Error, 4-Debugging Log ]
{
int fd;
time_t now;
ssize_t wlength=0;
char * dat;
char * str;
int size = 45+strlen(msg);//14+24+5+sizeof msg+1
str= (char *) malloc(size);
time(&now);//system time in seconds
dat = ctime(&now); // converting seconds to date-time format
dat = strtok(dat,"\n");
//Appending type of log
switch(typ)
{
case 1:
strcpy(str,"__LOG__ | ");
strcat(str,dat);
break;
case 2:
strcpy(str,"__WARN__ | ");
strcat(str,dat);
break;
case 3:
strcpy(str,"__ERR__ | ");
strcat(str,dat);
break;
case 4:
strcpy(str,"__DEBUG__ | ");
strcat(str,dat);
break;
default:
strcpy(str,"__UNDEF__ | ");
strcat(str,dat);
break;
}
strcat(str," | ");
strcat(str,msg);//appending message
strcat(str,"\n");
fd = open("log", O_WRONLY | O_CREAT | O_APPEND, 0644); // should be opened somewhere else
if (fd == -1)
printf("Could not open log - %s\n",strerror(errno));
else
{//need to add lock to the file and printing error message
while ( wlength < strlen(str) )
{
wlength = write(fd, str,strlen(str));
if (wlength == -1)
{
printf("Error : writing log\n");
break;
}
}
}
}
int sendall(int fd, char *buf, int *len)
{
int total = 0; // how many bytes we've sent
int bytesleft = *len; // how many we have left to send
int n;
while(total < *len) {
n = send(fd, buf+total, bytesleft, 0);
if (n == -1) { break; }
total += n;
bytesleft -= n;
}
*len = total; // return number actually sent here
return n==-1?-1:0; // return -1 on failure, 0 on success
}
int recvall(int fd, char *buf, int *len)
{
int total = 0; // how many bytes we've sent
int bytesleft = *len; // how many we have left to send
int n;
while(total < *len) {
n = recv(fd, buf+total, bytesleft, 0);
if (n == -1) { break; }
total += n;
bytesleft -= n;
}
*len = total; // return number actually sent here
return n==-1?-1:0; // return -1 on failure, 0 on success
}
void errorp(char *where, int boolean, int errn,char *what)
{
char errmsg[21+strlen(where)];
strcpy(errmsg,"Where - ");
strcat(errmsg,where);
strcat(errmsg," | Error - ");
if(boolean == 1)//we got error number
{
strcat(errmsg,strerror(errn));
//fprintf(stderr,"ERROR - In %s and error is %s\n",where ,strerror(errn));
logp(3,errmsg);
}
else if(boolean == 0)//we got a message
{
strcat(errmsg,what);
//fprintf(stderr,"ERROR - In %s and error is %s\n",where ,what);
logp(3,errmsg);
}
else//we got nothing
{
strcat(errmsg,"No Message");
//fprintf(stderr,"ERROR - In %s\n",where);
logp(3,errmsg);
}
}
Initially everything work fine but when I trid to use any function which is defined in accessories.c compilation give me error.
For example I use the log function in sendfdsock.c :
#include "accessories.h"
#define CONTROLLEN CMSG_LEN(sizeof(int))
static struct cmsghdr *cmptr = NULL; /* malloc'ed first time */
int send_err(int fd, int errcode, const char *msg);
int send_fd(int fd, int fd_to_send);
int main(int argc, char const *argv[])
{
logp(1,"started"); //This function is defined in accessories.c
int fd_to_send;
if((fd_to_send = open("vi",O_RDONLY)) < 0)
printf("vi open failed");
struct sockaddr_un address;
int socket_fd, nbytes;
char buffer[256];
........
Output of the compilation is:
abhi#abhi-me:~/bridge/server$ make compileAll
gcc -c sendfdsock.c
sendfdsock.c: In function ‘send_fd’:
sendfdsock.c:111:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘ssize_t’ [-Wformat]
sendfdsock.c:114:5: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘ssize_t’ [-Wformat]
gcc -o sendfdsock sendfdsock.o
sendfdsock.o: In function `main':
sendfdsock.c:(.text+0x32): undefined reference to `logp'
collect2: ld returned 1 exit status
make: *** [sendfdsock] Error 1
abhi#abhi-me:~/bridge/server$
Why undefined reference to logp error?
Why I don't write accessories.o in final linking:
But as this example is given in GNU Make Doc:
In this example, all the C files include ‘defs.h’, but
only those defining editing comminclude ‘command.h’, and only
low level files that change the editor buffer include 'buffer.h':
edit : main.o kbd.o command.o display.o \
insert.o search.o files.o utils.o
cc -o edit main.o kbd.o command.o display.o \
insert.o search.o files.o utils.o
main.o : main.c defs.h
cc -c main.c
kbd.o : kbd.c defs.h command.h
cc -c kbd.c
command.o : command.c defs.h command.h
cc -c command.c
display.o : display.c defs.h buffer.h
cc -c display.c
insert.o : insert.c defs.h buffer.h
cc -c insert.c
search.o : search.c defs.h buffer.h
cc -c search.c
files.o : files.c defs.h buffer.h command.h
cc -c files.c
utils.o : utils.c defs.h
cc -c utils.c
clean :
rm edit main.o kbd.o command.o display.o \
insert.o search.o files.o utils.o
Here while linking all the files in edit they don't write defs.o or buffer.o. Means while linking they are not including object files of header files. Also they have not written any target like: defs.o or buffer.o
Why?
You just missed accessories.o in both linking targets. Something like this:
accessories.o: accessories.c
sendfdsock: sendfdsock.o accessories.o
$(CC) -o $# $(CFLAGS) $(LDFLAGS) $+
Also, consider using the built-in rules, just modify their parameters, if needed. See make -p for the full list (and makes infopage)
You misunderstand the relationship between source files, header files and object files.
Suppose I have the following four files:
//foo.h
#define PI 3.1
//bar.h
void func();
//bar.c
#include "foo.h"
#include "bar.h"
void func()
{
...
}
//baz.c
#include "foo.h"
#include "bar.h"
int main()
{
func();
}
(I left out the header guards, I presume you know about those.) I must use the compiler to produce an object file from each source file: bar.c -> bar.o and baz.c -> baz.o. I don't have to make object files from the headers foo.h and bar.h, those will simply be #included by any source file that needs them. Then I link the object files together to form an executable:
baz: bar.o baz.o
gcc -o baz bar.o baz.o
bar.o: bar.c foo.h bar.h
gcc -c bar.c
baz.o: baz.c foo.h bar.h
gcc -c baz.c
If I neglect to link bar.o into the executable, I'll get a linker error when the linker gets to the place where baz calls func() and the linker doesn't know what to put there (because it lacks the definition of func() in bar.o):
baz.o: In function `main':
baz.c:(.text+0x32): undefined reference to `func()'
So the GNU Make doc is correct, and as Alex said, your rule should have:
sendfdsock:sendfdsock.o accessories.o
...
accessories.o: accessories.c accessories.h
...
(Incidentally, once you get this makefile working, we can show you how to make it more concise.)

undefined reference to `GlewInit' - OpenGL

I get this error when trying to make the executable, the code compiles correctly and yet when I hit the make command I get this error message:
gcc -c helloworld.c
lewis#lewis-desktop ~/Desktop/Dev/gl $ make
gcc -o hello-gl helloworld.o -L/usr/X11R6/lib -lGL -lglut -lGLEW -lm
helloworld.o: In function `Initialize':
helloworld.c:(.text+0x55): undefined reference to `GlewInit'
collect2: ld returned 1 exit status
make: *** [helloworld] Error 1
I'm running Linux Mint 13 and I think it's something to do with my makefile, I don't know too much about them so I hacked one together and found some code online:
GL_INCLUDE = /usr/X11R6/include
GL_LIB = /usr/X11R6/lib
GL_GLEW = /user/include
helloworld: helloworld.o
gcc -o hello-gl $^ -L$(GL_LIB) -lGL -lglut -lGLEW -lm
.c.o:
gcc -c -o $# $< -I$(GL_INCLUDE)
clean:
rm -f hello-gl hello-gl-dummy hello-gl.o util.o hello-gl-dummy.o
My Code:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <GL/glew.h>
#include <GL/freeglut.h>
#define WINDOW_TITLE_PREFIX "Hello, World!"
int CurrentWidth = 600,
CurrentHeight = 400,
WindowHandle = 0;
void Initialize(int, char*[]);
void InitWindow(int, char*[]);
void ResizeFunction(int, int);
void RenderFunction(void);
int main(int argc, char* argv[])
{
Initialize(argc, argv);
glutMainLoop();
exit(EXIT_SUCCESS);
return 0;
}
void Initialize(int argc, char* argv[])
{
GLenum GlewInitResult;
InitWindow(argc, argv);
GlewInitResult = GlewInit();
if (GLEW_OK != GlewInitResult) {
fprintf(stderr, "ERROR: %s\n", glewGetErrorString(GlewInitResult));
exit(EXIT_FAILURE);
}
fprintf(
stdout,
"INFO: OpenGL Version: %s\n",
glGetString(GL_VERSION)
);
glClearColor(0.2f, 1.0f, 0.8f, 0.3f);
}
void InitWindow(int argc, char* argv[])
{
glutInit(&argc, argv);
glutInitContextVersion(4, 0);
glutInitContextFlags(GLUT_FORWARD_COMPATIBLE);
glutInitContextProfile(GLUT_CORE_PROFILE);
glutSetOption(
GLUT_ACTION_ON_WINDOW_CLOSE,
GLUT_ACTION_GLUTMAINLOOP_RETURNS
);
glutInitWindowSize(CurrentWidth, CurrentHeight);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
char *states[] = {"Hello", "My", "Name", "Is", "Lewis"};
WindowHandle = glutCreateWindow(WINDOW_TITLE_PREFIX);
if(WindowHandle < 1) {
fprintf(
stderr,
"KERN_ERROR: Could not create a new rendering window.\n"
);
exit(EXIT_FAILURE);
}
glutReshapeFunc(ResizeFunction);
glutDisplayFunc(RenderFunction);
}
void ResizeFunction(int Width, int Height)
{
/*captures the resize data from the OS and assigns it to the global
variable CURRENT_WIDTH & CURRENT_HEIGHT */
CurrentWidth = Width;
CurrentHeight = Height;
glViewport(0, 0, CurrentWidth, CurrentHeight);
}
void RenderFunction(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
/*the next line takes the data from the back-buffer to the screen */
glutSwapBuffers();
glutPostRedisplay();
}
The names for the GLEW functions should start from 'glew', not 'Glew'.
So it is
GlewInitResult = glewInit();
C is case-sensitive and all the OpenGL-related libs usually start the names of the functions with lowercase letters.

Posix Semaphore compilation error using the -lrt [duplicate]

This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
sem_open() error: “undefined reference to sem_open()” on linux (Ubuntu 10.10)
Having issues with compilation of posix semaphores. My goal is to create a shared memory segment and protect it by semaphores. shared memory works fine but semaphores code gives me compilation errors even though I included semaphore.h and added -lrt to compilation flags
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <semaphore.h>
#include <time.h>
int main (int argc, char** argv) {
FILE *configFile;
int i,j;
int CashDesksNo=0;
int maxCashDesksNo;
int n,m;
int TmaxServe;
int custPerc; //customer ratio policy
int maxCapacity;
char * nlptr=NULL;
char * pch=NULL;
char line[125];
char termInput[30];
char tmpString[40];
int flg1,flg2;
int flag;
int execResult=0;
int fd;
int rc;
int randNum;
int status;
pid_t ch_pid;
int a,b,c;
int shmid=0;
int *shm_ptr;
int * err;
int retval;
sem_t *sp;
char semName[10];
strcpy(semName,"mutex");
//---------- Davasma kai elegxos in line parameters-----------------
// read inline params and config file
.
.
.
//------------ Print Configuration Data ----------------------------
if(CashDesksNo>maxCashDesksNo || CashDesksNo<1)
{
printf("\n# of Cash Desks should be between 1 and %d",maxCashDesksNo);
printf("\nsupermarket will now exit...\n");
exit(1);
}
printf("\n//-----------------------------------------------");
printf("\nSupermarket initialization");
printf("\n# of Cash Desks: %d",CashDesksNo);
printf("\n# of max products: %d",n);
printf("\nMax price: %d",m);
printf("\nMaximum serving time(secs): %d",TmaxServe);
printf("\n%% Customer/Cashier Percentage: %d/%d",custPerc,100-custPerc);
printf("\nMax Supermarket capacity: %d",maxCapacity);
printf("\n//-----------------------------------------------\n");
printf("\nAbout to create customer and cashier processes");
// ----------- Shared Memory Attachment --------------------------------
shmid=shmget(IPC_PRIVATE,sizeof(int*),0666);
if (shmid < 0)
{
perror("shmget");
exit(1);
}
shm_ptr=(int*)shmat(shmid,(void *)0,0);
if (shm_ptr == (int *)(-1))
{
perror("shmat");
exit(1);
}
a=0; //shm
shm_ptr=(int*)a;
printf("shmPtr:%d",(int)shm_ptr);
// ----- create & initialize semaphore ---------------------------------
sp = sem_open(semName,O_CREAT,0644,1);
if(sp == SEM_FAILED)
{
perror("unable to create semaphore");
exit(-1);
}
while(1)
{
printf("\nPress enter to start a new day at the supermarket(type exit to quit)\n");
fgets(termInput,sizeof(termInput),stdin);
nlptr = strchr(termInput, '\n');// termatismos string
if (nlptr) *nlptr = '\0';
if(strcmp(termInput,"exit")==0)//exit apo tin efarmogi
{
printf("\nExiting Supermarket..\n");
exit(0);
}
i=0;
while(i<maxCapacity)
{
//-Fork new process for the simulation --------------------
ch_pid = fork();
if (ch_pid == -1) {
perror("\nFailed to fork initial spliter/merger process \n");
exit(1);
}
if ( ch_pid == 0 ) //this is the child process
{
srand (getpid());//pid based seed
// "itoa" - Metatropi ari8mou se string
sprintf( tmpString, "%d", shmid );
randNum=rand() % 100 + 1;
if(randNum<custPerc)// customer : cashier ratio
{
execResult=execl("customer","customer","0",tmpString,NULL);
//printf("\nCreated a customer,randNum %d",randNum);
}else
{
execResult=execl("cashier","cashier","0",tmpString,NULL);
//printf("\nCreated a cashier,randNum %d",randNum);
}
if(execResult==-1)
{
perror("Could not perform exec to create cashier/customer process");
}
}
i++;
}
//Root process
//wait for childs to terminate
for (i = 0; i < maxCapacity; ++i)
{
waitpid(-1,&status,0);
}
printf("supermarket shared memory content: %d",(int)shm_ptr);
sem_close(sp);
sem_unlink(semName);
err = (int*)shmctl(shmid, IPC_RMID, 0);
if (err == -1)
perror ("Shared Memory Removal.");
else
printf("Shared Memory Removed. %d\n", (int)(err));
}
}
this is the makefile:
OBJS = supermarket.o cashier.o customer.o
SOURCE = supermarket.c cashier.c customer.c
HEADER = struct.h
OUT = supermarket cashier customer
CC = gcc
FLAGS = -lrt -g -c
LIBS = -lm
# -g option enables debugging mode
# -c flag generates object code for separate files
# -lm math library
all: supermarket cashier customer
supermarket: supermarket.c
$(CC) supermarket.c -o supermarket
cashier: cashier.c
$(CC) cashier.c -o cashier
customer: customer.c
$(CC) customer.c -o customer
# clean house
clean:
rm -f $(OBJS) $(OUT)
# do a bit of accounting
count:
wc $(SOURCE) $(HEADER)
I keep getting this error:
george#george-System-Product-Name:~/Desktop/prj3$ make
gcc supermarket.c -o supermarket
supermarket.c: In function ‘main’:
supermarket.c:310:11: warning: comparison between pointer and integer [enabled by default]
/tmp/ccYxA2Wi.o: In function `main':
supermarket.c:(.text+0x75c): undefined reference to `sem_open'
supermarket.c:(.text+0x9b0): undefined reference to `sem_close'
supermarket.c:(.text+0x9bf): undefined reference to `sem_unlink'
collect2: ld returned 1 exit status
make: *** [supermarket] Error 1
what can i do?
this is a project for operating systems class, my system is linux Ubuntu
I think you should link against pthread as well:
-lpthread
Example makefile from an old project of mine (see comments):
CC=gcc
CFLAGS=-c -Wall -O3 -g
LDFLAGS=-pthread
SOURCES=chatzor.c clientlist.c messagequeue.c
OBJECTS=$(SOURCES:.cpp=.o)
EXECUTABLE=chatzor_server
all: $(SOURCES) $(EXECUTABLE)
$(EXECUTABLE): $(OBJECTS)
$(CC) $(LDFLAGS) $(OBJECTS) -o $#
.cpp.o:
$(CC) $(CFLAGS) $< -o $#
clean:
rm -rf *.o ${EXECUTABLE}
You're going to have sore shins once you're done with this.
The compilation trace says:
$ make
gcc supermarket.c -o supermarket
supermarket.c: In function ‘main’:
...
Your makefile says:
supermarket: supermarket.c
$(CC) supermarket.c -o supermarket
It should say (at minimum):
supermarket: supermarket.c
$(CC) supermarket.c -o supermarket $(LIBS)
Indeed, it should probably be saying:
supermarket: supermarket.c
$(CC) $(CFLAGS) supermarket.c -o supermarket $(LDFLAGS) $(LIBS)

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