What I am really trying to achieve is an array of dynamic byte patterns that I can use as a pattern searcher when I buffer binary files. But I am starting off basic for now. I have the following code that I based off of an example found on StackOverflow.
How to Initialize a Multidimensional Char Array in C?
typedef unsigned char BYTE;
int main()
{
BYTE *p[2][4] = {
{0x44,0x58,0x54,0x31},
{0x44,0x58,0x54,0x00}
};
return 0;
}
I compile it with mingw32 for Windows.
D:\> gcc example.c -o example.exe
I get the following warnings when I try to compile.
example.c: In function 'main':
example.c:6:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:6:3: warning: (near initialization for 'p[0][0]') [enabled by default]
example.c:6:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:6:3: warning: (near initialization for 'p[0][1]') [enabled by default]
example.c:6:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:6:3: warning: (near initialization for 'p[0][2]') [enabled by default]
example.c:6:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:6:3: warning: (near initialization for 'p[0][3]') [enabled by default]
example.c:7:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:7:3: warning: (near initialization for 'p[1][0]') [enabled by default]
example.c:7:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:7:3: warning: (near initialization for 'p[1][1]') [enabled by default]
example.c:7:3: warning: initialization makes pointer from integer without a cast [enabled by default]
example.c:7:3: warning: (near initialization for 'p[1][2]') [enabled by default]
I don't understand the nature of this warning. How do I go about resolving it? Thanks.
Drop the * from BYTE *p[2][4]:
BYTE p[2][4] = {
{0x44,0x58,0x54,0x31},
{0x44,0x58,0x54,0x00}
};
You want a multidimensional array of char: BYTE p[2][4] not a multidimensional array of pointer-to-char.
Related
As I'm new to lexer and parser, so I'm trying to read and understand others code.
Here is the code i'm trying to use : https://gist.github.com/justjkk/436828
But it's giving me error. How can I resolve this?
E:\flex_bison_test>gcc lex.yy.c y.tab.c -o json.exe
json.l: In function 'yylex':
json.l:34:11: warning: assignment to 'YYSTYPE' {aka 'int'} from 'char *' makes integer from pointer without a cast [-Wint-conversion]
yylval=strclone(yytext);
^
json.l:38:11: warning: assignment to 'YYSTYPE' {aka 'int'} from 'char *' makes integer from pointer without a cast [-Wint-conversion]
yylval=strclone(yytext);
^
json.l: In function 'strclone':
json.l:82:15: warning: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
int len = strlen(str);
^~~~~~
json.l:82:15: warning: incompatible implicit declaration of built-in function 'strlen'
json.l:82:15: note: include '<string.h>' or provide a declaration of 'strlen'
json.l:79:1:
+#include <string.h>
%%
json.l:82:15:
int len = strlen(str);
^~~~~~
json.l:84:5: warning: implicit declaration of function 'strcpy' [-Wimplicit-function-declaration]
strcpy(clone,str);
^~~~~~
json.l:84:5: warning: incompatible implicit declaration of built-in function 'strcpy'
json.l:84:5: note: include '<string.h>' or provide a declaration of 'strcpy'
y.tab.c: In function 'yyparse':
y.tab.c:627:16: warning: implicit declaration of function 'yylex' [-Wimplicit-function-declaration]
# define YYLEX yylex ()
^~~~~
y.tab.c:1272:16: note: in expansion of macro 'YYLEX'
yychar = YYLEX;
^~~~~
y.tab.c:1540:7: warning: implicit declaration of function 'yyerror'; did you mean 'yyerrok'? [-Wimplicit-function-declaration]
yyerror (YY_("syntax error"));
^~~~~~~
yyerrok
json.y: At top level:
json.y:80:6: warning: conflicting types for 'yyerror'
void yyerror (char const *s) {
^~~~~~~
y.tab.c:1540:7: note: previous implicit declaration of 'yyerror' was here
yyerror (YY_("syntax error"));
^~~~~~~
E:\flex_bison_test>
Or these should remain as it is.
All the commands, I have given :
flex json.l
bison -dy json.y
gcc lex.yy.c y.tab.c -o json.exe
Simply:
#include <string.h>
in your flex definitions section on top of json.l should fix it for you.
There's also a Makefile in the repository you pointed to. Maybe you should use that. You don't seem to be generating the parser files properly. See comment below.
As for the remaining warnings:
warning: implicit declaration of function 'yyerror';
warning: implicit declaration of function 'yylex';
These can be easily fixed by adding declarations of yylex() and yyerror should be present in the bison prologue section at the top of your json.y:
%{
int yylex();
void yyerror(const char *s);
%}
As for these ones:
json.l:34:11: warning: assignment to 'YYSTYPE' {aka 'int'} from 'char *' makes integer from pointer without a cast [-Wint-conversion]
yylval=strclone(yytext);
^
json.l:38:11: warning: assignment to 'YYSTYPE' {aka 'int'} from 'char *' makes integer from pointer without a cast [-Wint-conversion]
yylval=strclone(yytext);
^
They're a bit more subtle. I would suggest have a look here on how to use yylval for correctly passing on strings from the lex's tokens into the parser's actions. The problem now is that yylval is a bare int but it ends up being assigned char pointers for both NUMBER and STRING tokens.
I am trying to initialize an array of structs that contain an array. Looking at
this and
this,
I think a pretty reasonable attempt is this:
struct Score_t{
int * dice;
int numDice;
int value;
};
struct Score_t Scores[NUMSCORES] = {
[0]={{0,0,0},3,1000},
[1]={{1,1,1},3,200},
[2]={{2,2,2},3,300},
[3]={{3,3,3},3,400},
[4]={{4,4,4},3,500},
[5]={{5,5,5},3,600},
[6]={{0},3,100},
[7]={{4},3,50}
};
However I can't get this to compile. Do you have any ways to get this done?
Edit: Forgot the error message: (snipped)
[5]={{5,5,5},3,600},
^
greed.c:79:2: warning: (near initialization for ‘Scores[5].dice’) [enabled by default]
greed.c:79:2: warning: initialization makes pointer from integer without a cast [enabled by default]
greed.c:79:2: warning: (near initialization for ‘Scores[5].dice’) [enabled by default]
greed.c:79:2: warning: excess elements in scalar initializer [enabled by default]
greed.c:79:2: warning: (near initialization for ‘Scores[5].dice’) [enabled by default]
greed.c:79:2: warning: excess elements in scalar initializer [enabled by default]
greed.c:79:2: warning: (near initialization for ‘Scores[5].dice’) [enabled by default]
greed.c:80:2: warning: braces around scalar initializer [enabled by default]
int * can't be initialized with { } (not match)
So change to like this.
struct Score_t Scores[NUMSCORES] = {
[0]={(int[]){0,0,0},3,1000},
[1]={(int[]){1,1,1},3,200},
[2]={(int[]){2,2,2},3,300},
[3]={(int[]){3,3,3},3,400},
[4]={(int[]){4,4,4},3,500},
[5]={(int[]){5,5,5},3,600},
[6]={(int[]){0},3,100}, //It doesn't know the number of elements
[7]={(int[]){4},3,50} //change to [7]={(int[3]){4},3,50} or [7]={(int[]){4},1,50}
};
I have the following code:
struct dmparam {
char *p;
char *v;
};
struct dmobj {
int a;
int b;
struct dmparam *dmparam;
};
struct dmarray {
struct dmobj *dmobj;
struct dmentry {
int func;
struct dmarray *dmarray;
} *dmentry;
};
struct dmarray atest = {
{//objs
{1, 11, NULL},
{2, 22,
{//params
{"p1", "v1"},
{"p2", "v2"},
}//params
}
},//objs
{//arays
{101, {
{//objs
{1, 11, NULL},
{2, 22,
{//params
{"p1", "v1"},
{"p2", "v2"},
}//params
}
},//objs
NULL
}
}
}//arrays
};
This code generate the following compilation warnings:
test.c:26:2: warning: braces around scalar initializer [enabled by default]
{//objs
^
test.c:26:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:27:2: warning: braces around scalar initializer [enabled by default]
{1, 11, NULL},
^
test.c:27:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:27:2: warning: initialization makes pointer from integer without a cast [enabled by default]
test.c:27:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:27:2: warning: excess elements in scalar initializer [enabled by default]
test.c:27:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:27:2: warning: excess elements in scalar initializer [enabled by default]
test.c:27:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:28:2: warning: braces around scalar initializer [enabled by default]
{2, 22,
^
test.c:28:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:28:2: warning: initialization makes pointer from integer without a cast [enabled by default]
test.c:28:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:28:2: warning: excess elements in scalar initializer [enabled by default]
test.c:28:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:29:3: warning: braces around scalar initializer [enabled by default]
{//params
^
test.c:29:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:30:3: warning: braces around scalar initializer [enabled by default]
{"p1", "v1"},
^
test.c:30:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:30:3: warning: initialization from incompatible pointer type [enabled by default]
test.c:30:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:30:3: warning: excess elements in scalar initializer [enabled by default]
test.c:30:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:31:3: warning: braces around scalar initializer [enabled by default]
{"p2", "v2"},
^
test.c:31:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:31:3: warning: initialization from incompatible pointer type [enabled by default]
test.c:31:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:31:3: warning: excess elements in scalar initializer [enabled by default]
test.c:31:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:31:3: warning: excess elements in scalar initializer [enabled by default]
test.c:31:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:32:3: warning: excess elements in scalar initializer [enabled by default]
}//params
^
test.c:32:3: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:33:2: warning: excess elements in scalar initializer [enabled by default]
}
^
test.c:33:2: warning: (near initialization for ‘atest.dmobj’) [enabled by default]
test.c:35:2: warning: braces around scalar initializer [enabled by default]
{//arays
^
test.c:35:2: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:36:3: warning: braces around scalar initializer [enabled by default]
{101, {
^
test.c:36:3: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:36:3: warning: initialization makes pointer from integer without a cast [enabled by default]
test.c:36:3: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:36:3: warning: braces around scalar initializer [enabled by default]
test.c:36:3: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:37:5: warning: braces around scalar initializer [enabled by default]
{//objs
^
test.c:37:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:38:5: warning: braces around scalar initializer [enabled by default]
{1, 11, NULL},
^
test.c:38:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:38:5: warning: initialization makes pointer from integer without a cast [enabled by default]
test.c:38:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:38:5: warning: excess elements in scalar initializer [enabled by default]
test.c:38:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:38:5: warning: excess elements in scalar initializer [enabled by default]
test.c:38:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:39:5: warning: braces around scalar initializer [enabled by default]
{2, 22,
^
test.c:39:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:39:5: warning: initialization makes pointer from integer without a cast [enabled by default]
test.c:39:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:39:5: warning: excess elements in scalar initializer [enabled by default]
test.c:39:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:40:6: warning: braces around scalar initializer [enabled by default]
{//params
^
test.c:40:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:41:6: warning: braces around scalar initializer [enabled by default]
{"p1", "v1"},
^
test.c:41:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:41:6: warning: initialization from incompatible pointer type [enabled by default]
test.c:41:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:41:6: warning: excess elements in scalar initializer [enabled by default]
test.c:41:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:42:6: warning: braces around scalar initializer [enabled by default]
{"p2", "v2"},
^
test.c:42:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:42:6: warning: initialization from incompatible pointer type [enabled by default]
test.c:42:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:42:6: warning: excess elements in scalar initializer [enabled by default]
test.c:42:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:42:6: warning: excess elements in scalar initializer [enabled by default]
test.c:42:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:43:6: warning: excess elements in scalar initializer [enabled by default]
}//params
^
test.c:43:6: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:44:5: warning: excess elements in scalar initializer [enabled by default]
}
^
test.c:44:5: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:47:3: warning: excess elements in scalar initializer [enabled by default]
}
^
test.c:47:3: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
test.c:47:3: warning: excess elements in scalar initializer [enabled by default]
test.c:47:3: warning: (near initialization for ‘atest.dmentry’) [enabled by default]
What I m doing wrong?
What's the best way to write this?
This code compiles as a complete source file:
struct dmparam {
char *p;
char *v;
};
struct dmobj {
int a;
int b;
struct dmparam *dmparam;
};
struct dmarray {
struct dmobj *dmobj;
struct dmentry {
int func;
struct dmarray *dmarray;
} *dmentry;
};
struct dmparam dp1 = { "abc", "xyz" };
struct dmparam dp2 = { "Mercury", "Uranus" };
struct dmobj do1 = { 1, 1, &dp1 };
struct dmobj do2 = { 2, -987, &dp2 };
struct dmentry de1 = { 0, 0 };
struct dmarray da1 = { &do1, &de1 };
Observe that you effectively have:
struct dmentry {
int func;
struct dmarray *dmarray;
};
struct dmarray {
struct dmobj *dmobj;
struct dmentry *dmentry;
};
So there are only two items in each struct dmarray, both pointers. Also, the struct dmentry is not restricted in scope; the rules in C++ are different.
All that is standard C90 code (as well as C99 and C11). In C99 or later, you can also do the initialization like this:
struct dmarray da2 =
{
.dmobj = &(struct dmobj){ 9, 99, &(struct dmparam){ "Frigid", "Roasting" } },
.dmentry = &(struct dmentry){ 1, &(struct dmarray){ 0, 0 } }
};
Note that you end up with needing a pointer to a struct dmarray while you're initializing another one. I ducked and use a null pointer in the nested structure, but you could go deeper if you wanted to.
Just for the record, the code was tested on Mac OS X 10.10.5 using 'gcc' (actually clang) from XCode 6.4:
$ gcc -std=c99 -pedantic -O3 -g -Wall -Wextra -Werror -c so.32014285.c
$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.5.0
Thread model: posix
$
There's an outside chance that despite requesting pedantic adherence to the C99 standard, GCC is letting an extension through.
I'm trying to write an MPI worker in C that will communicate with the MPI master, written in python. The master will send out scatters and gathers, and the C worker should receive those and return variables via gather. The problem is, I'm having trouble successfully writing the worker file.
(The reason the worker is in C is because this code is a skeleton to wrap around preexisting python and C programs.)
Here is the code I've written:
#include <stdio.h>
#include <mpi.h>
MPI_Comm comm;
MPI_Comm_get_parent(&comm);
int myid, world_size, size;
int root = 0;
int* endloop = malloc(sizeof(int));
int nelements1 = 1E3;
int nelements2 = 1E6;
float* input = malloc(sizeof(float) * nelements1);
float output[nelements2];
int randomarray(){
float array[nelements2];
srand(time(NULL));
for( i = 0; i < nelements2; i++ ){
array[i] = rand() % 0 + 1E6;
}
return array;
MPI_Comm_rank(MPI_COMM_WORLD, &myid);
MPI_Comm_size(MPI_COMM_WORLD, &world_size);
MPI_Comm_remote_size(comm, &size);
output = randomarray();
MPI_Scatter(endloop, 1, MPI_INT, root, comm);
while ( endloop[0] < 1) {
MPI_Barrier(comm);
MPI_Scatter(input, nelements1, MPI_FLOAT, root, comm);
MPI_Barrier(comm);
MPI_Gather(output, nelements2, MPI_FLOAT, root, comm);
MPI_Scatter(endloop, 1, MPI_INT, root, comm);
}
MPI_Finalize();
And the error output when I attempt to compile is:
maddie#exo:~/code/bart_commloop$ mpicc worker.c -o worker
worker.c:5:21: error: expected declaration specifiers or ‘...’ before ‘&’ token
worker.c:9:16: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default]
worker.c:9:1: error: initializer element is not constant
worker.c:12:1: error: initializer element is not constant
worker.c:13:7: error: variably modified ‘output’ at file scope
worker.c: In function ‘randomarray’:
worker.c:18:7: error: ‘i’ undeclared (first use in this function)
worker.c:18:7: note: each undeclared identifier is reported only once for each function it appears in
worker.c:19:21: warning: division by zero [-Wdiv-by-zero]
worker.c:22:2: warning: return makes integer from pointer without a cast [enabled by default]
worker.c:22:2: warning: function returns address of local variable [enabled by default]
worker.c:28:8: error: incompatible types when assigning to type ‘float[1]’ from type ‘int’
worker.c:30:1: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:30:1: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:30:1: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:34:2: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:34:2: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:34:2: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:36:2: warning: passing argument 4 of ‘MPI_Gather’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1058:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:36:2: warning: passing argument 5 of ‘MPI_Gather’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1058:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:36:2: error: too few arguments to function ‘MPI_Gather’
/usr/lib/openmpi/include/mpi.h:1058:20: note: declared here
worker.c:37:2: warning: passing argument 4 of ‘MPI_Scatter’ makes pointer from integer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘void *’ but argument is of type ‘int’
worker.c:37:2: warning: passing argument 5 of ‘MPI_Scatter’ makes integer from pointer without a cast [enabled by default]
/usr/lib/openmpi/include/mpi.h:1197:20: note: expected ‘int’ but argument is of type ‘MPI_Comm’
worker.c:37:2: error: too few arguments to function ‘MPI_Scatter’
/usr/lib/openmpi/include/mpi.h:1197:20: note: declared here
worker.c:40:1: error: expected declaration or statement at end of input
The issue seems to be the formatting of my MPI calls, but I'm not sure what to fix there.
Any help would be greatly appreciated. Thank you!
I get this error.
error: warning: incompatible implicit declaration of built-in function ‘memcpy’ [enabled by default]
This is the code:
int arr[ 12] = {1,0,0,0,0,0,0,0,0,0,9370, 0};
void *a = &arr;
memcpy(machine->mem, a,12*4);
What I am doing wrong?
You likely forgot to include <string.h>.
Add #include <string.h> to the top of your file.