Add GCC options to top of C source file

Question

Is is possible to put something at the top of the C source file, like

// GCC_OPTIONS=-g,-Wall

that will add those options automatically to gcc every time you compile this file?

Plymouth

Answer 1

Yes it is, at least for some flags. You can push and pop diagnostic settings like this:

#pragma GCC diagnostic error "-pedantic"
#pragma GCC diagnostic warning "-Wall"

This is also possible for optimization levels on a per-function level:

#pragma GCC optimize ("string"...)

These #pragma definitions affect all code after them in a source file.

See these other questions for more information:

• Switching off optimization for a specific function in gcc 4.2.2
• Selectively disable GCC warnings for only part of a translation unit?

Crossfertilization

Neither of these are equivalent to the options he's asking about. – Strapless

@MatthewFlaschen These settings affect all functions defined later in a source file, so to some extent they can be equivalent: put them on the top and they kind of become global. – Corrugate

No debug unfortunately it seems: #2007321 – Lempres

Is there a pragma for setting an -f/-fno flag (e.g., ` -fno-ipa-icf`)? – Struthious

Answer 2

No. Some compiler options have #define equivalents, but not those. This belongs in your make file (or equivalent). With GNU Make:

CFLAGS += -g -Wall

Strapless

-Wall has an in source equivalent. – Crossfertilization

@Matt, what is it? Your answer doesn't give one, and #pragma GCC diagnostic warning "-Wall" definitely doesn't work in GCC 4.4. – Strapless