gcc -Wall option flag


gcc -Wall option flag

gcc -Wall enables all compiler's warning messages. This option should always be used, in order to generate better code.



$ gcc -Wall [options] [source files] [object files] [-o output file]



Write source file myfile.c:

// myfile.c
#include <stdio.h>

int main()
    printf("Program run!\n");
    int i=10;


Regular build of myfile.c gives no messages:

$ gcc myfile.c -o myfile


Build of myfile.c with -Wall:

$ gcc -Wall myfile.c -o myfile
myfile.c In function 'main':
myfile.c:6:6: warning: unused variable 'i'
myfile.c:7:1: warning: control reaches end of non-void function




See also

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