CODEWITHSUNDEEP
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Rami Rosenbaum
Rami Rosenbaum

Reputation: 477

IAR Embedded Workbench: stdarg.h isn't preprocessed

I'm building a c-language application, using IAR Embedded Workbench for ARM 7.40.
I'm using libclang to get an AST (abstract syntax tree) representation of my c-code. For that, I'm preprocessing my source-code.
The problem is with #include <stdarg.h> - it doesn't get expanded.

Original code snippet: 

int before_stdarg = 1;
#include <stdarg.h>
int after_stdarg = 2;
va_list args;
#include "func1.h"
...

Preprocessed code snippet: 

#line 1 "source\\App\\func1.c"
int before_stdarg = 1;
#include <stdarg.h>
int after_stdarg = 2;
va_list args;
#line 1 "C:\\testAppC\\source\\App\\func1.h"
...

Viewing stdarg.h:

#ifdef __ICCARM__
#error "Reading built-in header-file. If you used upper case, try #include <stdarg.h>"
#endif

A second issue: where is va_list defined?
commenting out #include <stdarg.h> results in a compilation error: Error[Pe020]: identifier "va_list" is undefined

What am I missing?

Update, due to comments:
The Q is not for IAR EWARM newbies, as the marked answer can hint.
The issue occurs on any minimal hello-world example, simply by adding the #include <stdarg.h>, without even using it!
The preprocess command is a copy-paste of the regular build command, with the --preprocess=l PATH_TO_PREPROCESSED_OUTPUT_FILE addition: 

PS C:\testAppC> iccarm.exe source\App\func1.c -DSTM32L476xx -DUSE_HAL_DRIVER -I"C:\Program Files (x86)\IAR Systems\Embedded Workbench 7.2\arm\CMSIS\Include" -I"C:\Program Files (x86)\IAR Systems\Embedded Workbench 7.2\arm\inc\c" -I"source\App" -I"source\Device" --char_is_signed --cpu=Cortex-M4 --debug --dlib_config  "C:\Program Files (x86)\IAR Systems\Embedded Workbench 7.2\arm\INC\c\DLib_Config_Normal.h" --endian=little --fpu=None --no_clustering --no_code_motion --no_cse --no_inline --no_scheduling --no_tbaa --no_unroll -On -e -o testAppC\Obj --preprocess=l C:\testAppC\.aurora\tmp\func1.c.i

Upvotes: 1

Views: 1074

Answers (2)

Antti Haapala -- Слава Україні
Antti Haapala -- Слава Україні

Reputation: 133929

As a general remark, the headers specified in <...> need not be separate files on disk, but can be built in to the compiler, and need only be expanded during the preprocessing phase of the compilation as if they were code pasted in the place of the #include directive.

In fact, the standard says that the other include form of "..." includes source files, so the standard itself does not even use a term "header file" at all - there are only headers or source files.

Upvotes: 1

Johan
Johan

Reputation: 3881

In iccarm 7.40 the stdarg.h in the filesystem is only a stub file. The varargs machinery is built into the compiler and activated by the #include <stdarg.h> directive. This is also why this include directive is not expanded when using the --preprocess command line option. This was changed recently and as of iccarm 8.40 the compiler uses the stdarg.h from the file system.

Upvotes: 3

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