CODEWITHSUNDEEP
clinuxgcc
lokesharo
lokesharo

Reputation: 305

Object file name displayed in a warning during the compilation process changing on every invocation of the compiling process

I am compiling a function and getting warning:

**/tmp/ccPFK7nG.o: warning gets is dangerous and should not be used.**

Now I know why the warning is coming, the part that I am not aware is the location from where the warning is coming keeps changing. Every time I compile the code the location is /tmp/some_file.o Is it like gcc makes the temporary object file in /tmp directory and when the executable is made it removes it from there?

Upvotes: 1

Views: 144

Answers (3)

glglgl
glglgl

Reputation: 91017

If compiling and linking at the same time, such as 

gcc a.c b.c c.c -o wholeprogram

each mentioned C module gets compiled into a temporary object file, then all object files are linked together to get the final executable.

The names of these temporary obejct files are created dynamically and on the fly and, thus, change on every invocation.

Upvotes: 1

Turbo J
Turbo J

Reputation: 7691

Every time I compile the code the location is /tmp/some_file.o Is it like gcc makes the temporary object file in /tmp directory and when the executable is made it removes it from there?

What you see is a side effect of the -flto option in gcc, that enables link time optimization. The compiled source for this second pass is indeed a temporary, containing precompiled data from object files.

To see the real culprit, you may need to remove this option and recompile, although the warning should appear with the correct file location in the first pass.

Upvotes: 2

Jeyaram
Jeyaram

Reputation: 9474

Suggest to remove the usage of gets(). Since ISO C11 removes the specification of gets() from the C language.

http://linux.die.net/man/3/gets

Read BUGS and Conforming to section.

Upvotes: 1

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