View function prototypes in C [closed] - c

Question

Closed. This question needs to be more focused. It is not currently accepting answers.
Want to improve this question? Update the question so it focuses on one problem only by editing this post.
Closed 6 years ago.
Improve this question
Often during programming contests I forget which library contains which function. Hence I require some C code which can print the available functions with a specific library. eg. usage:
showAvailFunctions("stdlib.h")
and it would print all the available functions with stdlib.h library

Answer 1

Create a C program file with the include directive for the include file you want to see.
For instance:
#include <stdlib.h>
Compile with Preprocessor output to generate a file, usually a file with an extension of .i and you will have the complete contents of the include file.
For Visual Studio, you may need to indicate whether you want to keep the comments or not.
The output file should appear in your working directory.
A more involved example of an approach is as follows. This is a C source text file which does a series of includes with special markers to show what is where.
The program at the bottom of the source file is a simple filter program which reads the C Preprocessor file generated and removes most of the clutter such as blank lines or those "#line " lines of output which specify a line number and the file it came from.
You will need to add whatever include files you want to see. Then compile it twice, once with C Preprocessor output enabled to generate a file containing the C Preprocessor output and once with C Preprocessor output disabled to generate an actual executable file. Your C compiler may provide options to do both steps in a single compile. I could not see how to do that with Visual Studio 2013.
Here is an example source file. I expect you may need to tailor this for your compiler and development environment. This compiles and generates output with Visual Studio 2013. I created a simple .bat file which runs this application from the command line and redirect STDOUT to a text file that contains the filtered C Preprocessor output.
#define MAKE_SEP_STRING "<!-- #$%^&*()_+-=qwrtv -->"
#define MAKE_SEP_STRING_END "<!--END #$%^&*()_+-=qwrtv -->"
#define MAKE_SEP_BEGIN(x) static const char X_##x [] = MAKE_SEP_STRING #x;
#define MAKE_SEP_END
MAKE_SEP_BEGIN(stdio);
#include <stdio.h>
MAKE_SEP_BEGIN(stdlib);
#include <stdlib.h>
MAKE_SEP_END
#include <string.h>
int main(int argc, char* argv[])
{
if (argc < 2) {
printf("output file must be specified.\n");
return 1;
}
else {
char *sep = MAKE_SEP_STRING_END; // if we want to determine where each file begins or ends.
FILE *pFile;
fopen_s(&pFile, argv[1], "r");
if (pFile) {
char hugeBuffer[4096];
// read through the C Preprocessor output file and eliminate empty lines.
// there can be a lot of empty lines.
while (fgets(hugeBuffer, 4000, pFile)) {
if (strlen(hugeBuffer) > 5) {
// discard all those tons of #line n text lines generated by the Preprocessor
if (strncmp(hugeBuffer, "#line ", 6) == 0) continue;
if (strcmp(hugeBuffer, sep) == 0)
{
break;
}
printf("%s\n", hugeBuffer);
}
}
fclose(pFile);
}
}
return 0;
}