"Go" gcc warnings at all levels #pragma gcc diagnostic ignored "-wunused-parameter"--good

Original URL: http://blog.csdn.net/lizzywu/article/details/9419145

GCC warnings at each level
Overrides


Variable (code) level from top to bottom: Specify a variable warning


int a __attribute__ ((unused));
Specifies that the variable is unused. Even if the variable is not used, a warning output is ignored at compile time.


File-level: diagnostics (Ignore/warn) in source code file


Syntax:


#pragma GCC diagnostic [error|warning|ignored] "-w< Warning Options >
Diagnostics-Ignore: (Turn off warning)


#pragma  gcc diagnostic ignored   "-wunused"
#pragma  gcc Diagnostic ignored   "-wunused-parameter"
Diagnostics-Warning: (Open warning)


#pragma  gcc diagnostic warning   "-wunused"
#pragma  gcc diagnostic warning   "-wunused-parameter"
Diagnostics-Error: (Turn on warning-upgrade to error)


# pragma  gcc diagnostic error   "-wunused"
#pragma  gcc diagnostic error   "-wunused-parameter"
Usage:


Closes the warning at the beginning of the file and then opens the warning at the end of the file, which ignores the specified warning in the file.


Project-level: command line/compile parameter specifies


Warning:
gcc main.c-wall ignored:
gcc mian.c-wall-wno-unused-parameter//Open All warning, However, the-unused-parameter warning


option format:-w[no-]< warning option is ignored,
such as:-wno-unused-parameter # no-indicates that the warning is ignored during diagnostics

Source: https://github.com/zodiac1111/note/blob/master/note/gcc/gcc-ignored-warning.markdown#%E6%96%87%E4%BB%B6%E7% Ba%a7%e5%9c%a8%e6%ba%90%e4%bb%a3%e7%a0%81%e6%96%87%e4%bb%b6%e4%b8%ad%e8%af%8a%e6%96%ad%e5%bf%bd%e7%95%a5%e8%ad %a6%e5%91%8a

6.59.10 Diagnostic Pragmas

GCC allows the user to selectively enable or disable certain types of diagnostics, and the kind of the diagnostic. For example, a project's policy might require that all sources compile with but -Werror certain files might has exceptions Allowing specific types of warnings. Or, a project might selectively enable diagnostics and treat them as errors depending on which preprocessor macros is def ined.

#pragma GCC diagnostic  kind option

Modifies the disposition of a diagnostic. Note that not all diagnostics is modifiable; At the moment-warnings (normally controlled by ' -W...') can is controlled, and not all of them. Use -fdiagnostics-show-optionTo determine which diagnostics is controllable and which option controls them.

kindIs " error to treat" diagnostic as an "error," to warning treat it like a warning (even if are -Werror in effect), or ' ' If the diagnostic is to be ignored. is option a double quoted string that matches the command-line option.

          #pragma gcc diagnostic warning "-wformat"          #pragma gcc diagnostic error "-wformat"          #pragma gcc diagnostic ignored "-wformat"

Note that these pragmas override any command-line options. GCC keeps track of all pragma, and issues diagnostics according to the state as of CE file. Thus, pragmas occurring after a line does not affect diagnostics caused by.

#pragma GCC diagnostic push

#pragma GCC diagnostic pop

Causes GCC push to remember the state of the diagnostics as of each, and a restore to that point at each pop . If a pop has no matching push , the command-line options is restored.

          #pragma GCC diagnostic error "-wuninitialized"            foo (a);                       /* error is given for this one/*          #pragma gcc diagnostic push          #pragma gcc diagnostic ignored "-wuninitialized" 
     foo (b);                       /* No diagnostic for this one          /* #pragma GCC diagnostic pop            foo (c);                       /* error is given for this one          /* #pragma GCC diagnostic pop            foo (d);                       /* depends on command-line options */

GCC also offers a simple mechanism for printing messages during compilation.

#pragma message  string

Prints as string a compiler message on compilation. The message is informational only, and was neither a compilation warning nor an error.

          #pragma message "compiling" __file__ "..."

stringMay was parenthesized, and is printed with the location information. For example,

          #define DO_PRAGMA (x) _pragma (#x)          #define TODO (x) do_pragma (Message ("Todo-" #x))                    TODO (Remember to fix this)

Prints ' /tmp/file.c:4: note: #pragma message: TODO - Remember to fix this .

Source: http://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html

Example

#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-wunused-label"
....

#pragma GCC diagnostic POPs

"Go" gcc warnings at all levels #pragma gcc diagnostic ignored "-wunused-parameter"--good