Hi I have several questions. I will be glad if someone will answer :)
I'm trying to compile linux driver for an lcd 16X2 module.
I'm trying to use in my code the struct file_operations();
1. I notice by other codes that they add #ifdef KERNEL21 to compile. I tryed to this and I got much less errors. why it's work this way. im using kernel 2.6.18-128.4.1.el5.. soo do I need to change to #ifdef KERNEL26? I get more errors if I try to do soo.
2.some of the file_operation arguments are function the rtuen ssize_t. what is this mean? in other code eample there is also "#ifdef KERNEL21" but still I get an error:
"lcd_module.c:74: error: expected identifier or ג(ג before ג{ג token"
3.last qustion, I worked with a Makfile example and I get .o file and not .ko that im use to work with. how do I run the module with the .o file?
thank on advance :)
ssize_t is basically a signed size_t and is widely used in the kernel because values less than zero are used to return errors in places where an unsigned size is expected. For example, the read file operation is expected to return the number of bytes read, but in case of insufficient memory you can return -ENOMEM and errno will be set appropriately in the user-space program.
With the 2.6 kernel you are supposed to use the Makefile from the kernel-headers package rather than a hand-crafted one, and it produces a .ko file rather than an .o. Further reading here: http://www.cyberciti.biz/tips/build-linux-kernel-module-against-installed-kernel-source-tree.html
Related
I'm developing something on Minix 3 and, when it comes to deal with io files, I got a problem.
In the code:
#include <stdio.h> /* If I don't call any stdio funcs compiler doesnt's complain*/
int main() {
FILE * fp; /* I get the following: " * not expected " */
return 0;
}
Already tried everything that comes to my mind, can't figure it out..
/EDIT/
From what I can tell, when I include something, if I call functions not related to structs, it's OK. Is it the structs ?
I will assume you have checked whether the Minix file is present, that it really defines the type FILE and that your include path provides the correct -Ioption to the compiler to find that file.
Depending on your environment it could happen that an environment variable INCLUDE exists and is recognized by your compiler to provide additional include paths, recognized even before the include options from the command line. In such a case it might happen to include a stdio.hfrom a different compiler. Visual Studio is known to provide such an environment variable by default, and that has bitten me once before.
EDIT: Running the preprocessor in isolation may help to find out what is really happening in any case. Verify that FILEis defined in the preprocessed version of your file.
I'm trying to cross compile my application for the maemo environment (GNU).
When compiling the application normally, everything works fine, however when it's compiled through sb2 the following warning comes up:
$ sb2 gcc -D_GNU_SORCE -o app -Wall -g -I.......//don't think this is relevant
In file included from wifi_collector_menu.c:50:
wifi_collector_list.c: In function `show_net_apns':
wifi_collector_list.c:777: warning: implicit declaration of function `getline'
I am completely confused as to why this happens, there are other getlines that do work in the program, i have tried to define the variable _GNU_SOURCE both inside the code and in the compiler command (not at the same time)
This is the line of code which causes the warning apparently:
size_t bytesnum = MAX_ESSID;
size_t bytes_read;
char *netname = NULL;
printf("Enter name of selected network:");
bytes_read=getline(&netname,&bytesnum,stdin);//This line
Any help would be appreciated, thanks in advance.
Problem solved, all I had to do was add:
#define _GNU_SOURCE
In each header file, before stdio.h was included, very simple really.
I guess this info is assumed known between programmers as i was unable to find it anywhere online, and had to ask my C programming professor personally, and even then we had some trouble tracing the source.
Thanks anyway.
Change your compiler line to include the -E option and redirect the output. The compiler will only pre-proccess your file when this option is used. Do this for both versions, with and without sb2. getline() is normally found in stdio.h. By viewing the preprocessed output from both versions, you should be able to see where getline() is being included from.
I am seeing a strange issue while implementing the readdir() functionality in fuse. Basically when I do ls on any directory in fuse, I get an error such as:
# ls
ls: reading directory .: Input/output error
file1.c file2.c
But the strange thing is, readdir() is doing exactly what it is supposed to do. In the sense that in that particular directory, I have two files named file1.c and file2.c and it is able to read it correctly.
While debugging the issue I noticed that fuse filler function (fuse_fill_dir_t passed as an argument to readdir() ) is what may be causing this error.
This is because if I simply print the contents of the directory using a debug printf without returning the contents using the filler function, I do not see the error.
But as soon as I start using the filler function to return the contents, I start seeing this error.
I have two questions related to this:
1) Anybody have any idea as to why the filler function might be causing this problem?
2) How do I look for the definition of the code for the fuse_fill_dir_t function? I have looked through most of the fuse functions with that kind of arguments but have had no luck until now.
Any help is appreciated!
Cheers,
Vinay
Such messages may be caused by failed calls to other (possibly unimplemented) FUSE callbacks like getxattr(). Then readdir() is called and results are obtained right.
You can debug a FUSE filesystem running its executable with key -d (debug mode), - that does not daemonize process and prints detailed debug output about FUSE calls.
Also, it would be nice to know what is your platform (Linux/OS X/etc).
I have been trying to compile netcat.c on AIX for some time (using the command make aix), but the compiler gives me some weird feedback such as :
"netcat.c", line 117.12: 1506-275 (S) Unexpected text 'int' encountered.
when checked the file netcat.c at line 117, I would find the line (second line in code below):
#ifdef HAVE_BIND
extern int h_errno;
/* stolen almost wholesale from bsd herror.c */
even if I changed the int into char for the same of testing, save the file and re-run the command I get the same error
am I missing something in reading the error code?
If you're using xlc (especially older ones), it's normally caused by declarations after statements, something like:
i = i + 1;
int x;
You probably need to give us a little more context, such as 10 or so lines before the error line.
My advice would be to get gcc running on that box if you are using an older xlc. IBM makes some fine compilers now but the earlier ones weren't so crash hot (in my opinion).
When innocent-looking code produces bizarre errors, try running the code through the C preprocessor stage, and looking at it then. Sometimes macros do very funny things.
Also note that a problem on an earlier line (missing semicolon, etc.) might produce an error message on a later line.
The post maybe already a little outdated, but just in case someone else comes along with the same problem ...
Here (AIX 7.1) h_errno is defined as macro in netdb.h.
/usr/include/netdb.h:#define h_errno (*(int *)h_errno_which())
Therefore the declaration in netcat.c line 117 does not work.
I just changed the line into
#ifndef h_errno
extern int h_errno;
#endif
and the compilation worked smoothly.
#A.Rashad, I moved the HAVE_BIND #ifdef block from line 117 to line 30 which is just under the #include "generic.h" declaration. This permitted the xlc to compile it. The (S)yntax error messages are gone and while there are some (W)arning messages, I do get an nc binary at the end!
hth,
Kevin
I’m trying to initialize the Metal C environment with the following code, but get the following errors on the memset line.
ERROR CCN3275 IMIJWS0.METAL.SAMPLIB(MEM):6 Unexpected text ')' encountered.
ERROR CCN3045 IMIJWS0.METAL.SAMPLIB(MEM):6 Undeclared identifier ___MEMSET.
ERROR CCN3277 IMIJWS0.METAL.SAMPLIB(MEM):6 Syntax error: possible missing ')' or ','?
CCN0793(I) Compilation failed for file //'IMIJWS0.METAL.SAMPLIB(MEM)'. Object file not created.
Below is my code
#include < string.h>
#include < stdlib.h>
#include < metal.h>
void mymtlfcn(void) {
struct __csysenv_s mysysenv;
memset ( &mysysenv, 0, sizeof ( mysysenv ) );
mysysenv.__cseversion = __CSE_VERSION_1;
mysysenv.__csesubpool = 129;
mysysenv.__cseheap31initsize = 131072;
mysysenv.__cseheap31incrsize = 8192;
mysysenv.__cseheap64initsize = 20;
mysysenv.__cseheap64incrsize = 1;
The issue was with the search order. Although I did search(/usr/metal/include) from with in my JCL I didn't proceed it with a nosearch option, so string.h was getting picked up from the standard system librarys instead of the version included with Metal C. I've pasted my optfile dataset I passed to the CPARM below for refference.
//OPTIONS DD *
SO
LIST
LONG
NOXREF
CSECT
METAL
LP64
NOSEARCH
search(/usr/include/metal/)
So, I have no idea. But some suggestions:
You might try copying/pasting this code here from this example just to make sure it works 'as expected'
Maybe try defining some of the macros here? (when I did C programming on zOS, I had to do include some weird macros in order to get stuff to work. I have no reasonable technical explanation for this.)
You could try searching for memset() using "=3.14" (from ispf.) See if any other modules use that function, and then check the headers that they include (or macros that they define - either in the C files or H files) to make it work.
Another thought: before the memset(), try doing putting a printf() in. If you get a syntax error on the same line (only for printf, rather than memset) then you can see if the problem is before line 6 - like a misplaced parenthesis.
Finally, if i recall correctly, I had to compile my individual modules, and then link them manually (unless I wrote a JCL to do this for me.) So you might have to link once to link with your other modules, and then link again against the C library. Not to be pedantic, but: you're fairly certain that you're doing all of the link passes?
I realize that's a lot of hoops to try and you've probably already read the manuals, but maybe there is something useful to try?
Also, and you probably already know this, but this site (for looking up error codes) is infinitely useful. (along with the above links for full-text-searching the manual)
Edit: this page also talks about "built-in functions" - you could try (as stated at the bottom of the page) "#undef memcpy" to use the non-built-in version?
Can you show us your compiler arguments? You need to make sure that you're not pulling in the standard C header files in addition to the metal C ones. Here's an example:
xlc -c -Wc,metal,longname,nosearch,'list(./)' -I. -I /usr/include/metal -I "//'SYS1.SIEAHDRV'" -S -qlanglvl=extended foo.c
as -mrent -mgoff -a=foo.list -o foo.o foo.s
ld -bac=1 -brent -S "//'SYS1.CSSLIB'" -o foo foo.o
Are you missing the closing brace '}' for the function? How about any missing semi-colon line terminators? When missing braces/semi-colons the z/OS C compiler throws some strange/misleading messages sometimes. I don't have it to try out, but I'm assuming Metal does as well.