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Top Forums Programming Segmentation fault in fopen when in write mode. Post 302673055 by achenle on Tuesday 17th of July 2012 11:41:16 AM
Old 07-17-2012
Quote:
Originally Posted by shoaibjameel123
I would agree with Corona688. I could not express this very well in my reply. My objective is to keep the values to 32bit ints only.

....
And that makes your code non-portable. The C standard specifies
Code:
int main( int, char ** )

Note that 16, 32, or 64 bit integral values are not specified - how many bits are in an "int" is an implementation-specific detail.


If you use
Code:
int32_t main( int32_t, char **)

you'll find another source of SEGVs if you specify "int32_t" on any architecture where an integer is implemented as anything other than 32 bits. In that case, the argc argument to main() will be placed on the stack as 64-bit value, say, and your code will pull it off as 32-bit value. Then value of argc your code sees will be way off, and the argv pointer value your code uses will most likely point off into la-la land.
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TCC(1)																	    TCC(1)

NAME
tcc - Tiny C Compiler SYNOPSIS
usage: tcc [options] [infile1 infile2...] [-run infile args...] DESCRIPTION
TCC options are a very much like gcc options. The main difference is that TCC can also execute directly the resulting program and give it runtime arguments. Here are some examples to understand the logic: "tcc -run a.c" Compile a.c and execute it directly "tcc -run a.c arg1" Compile a.c and execute it directly. arg1 is given as first argument to the "main()" of a.c. "tcc a.c -run b.c arg1" Compile a.c and b.c, link them together and execute them. arg1 is given as first argument to the "main()" of the resulting program. "tcc -o myprog a.c b.c" Compile a.c and b.c, link them and generate the executable myprog. "tcc -o myprog a.o b.o" link a.o and b.o together and generate the executable myprog. "tcc -c a.c" Compile a.c and generate object file a.o. "tcc -c asmfile.S" Preprocess with C preprocess and assemble asmfile.S and generate object file asmfile.o. "tcc -c asmfile.s" Assemble (but not preprocess) asmfile.s and generate object file asmfile.o. "tcc -r -o ab.o a.c b.c" Compile a.c and b.c, link them together and generate the object file ab.o. Scripting: TCC can be invoked from scripts, just as shell scripts. You just need to add "#!/usr/local/bin/tcc -run" at the start of your C source: #!/usr/local/bin/tcc -run #include <stdio.h> int main() { printf("Hello World "); return 0; } TCC can read C source code from standard input when - is used in place of infile. Example: echo 'main(){puts("hello");}' | tcc -run - OPTIONS
-v Display current TCC version, increase verbosity. -print-search-dirs Print the name of the configured installation directory and a list of program and library directories tcc will search. -c Generate an object file. -o outfile Put object file, executable, or dll into output file outfile. -Bdir Set the path where the tcc internal libraries can be found (default is PREFIX/lib/tcc). -bench Output compilation statistics. -run source [args...] Compile file source and run it with the command line arguments args. In order to be able to give more than one argument to a script, several TCC options can be given after the -run option, separated by spaces. Example: tcc "-run -L/usr/X11R6/lib -lX11" ex4.c In a script, it gives the following header: #!/usr/local/bin/tcc -run -L/usr/X11R6/lib -lX11 #include <stdlib.h> int main(int argc, char **argv) { ... } Preprocessor options: -Idir Specify an additional include path. Include paths are searched in the order they are specified. System include paths are always searched after. The default system include paths are: /usr/local/include, /usr/include and PREFIX/lib/tcc/include. (PREFIX is usually /usr or /usr/local). -Dsym[=val] Define preprocessor symbol sym to val. If val is not present, its value is 1. Function-like macros can also be defined: -DF(a)=a+1 -Usym Undefine preprocessor symbol sym. Compilation flags: Note: each of the following warning options has a negative form beginning with -fno-. -funsigned-char Let the "char" type be unsigned. -fsigned-char Let the "char" type be signed. -fno-common Do not generate common symbols for uninitialized data. -fleading-underscore Add a leading underscore at the beginning of each C symbol. Warning options: -w Disable all warnings. Note: each of the following warning options has a negative form beginning with -Wno-. -Wimplicit-function-declaration Warn about implicit function declaration. -Wunsupported Warn about unsupported GCC features that are ignored by TCC. -Wwrite-strings Make string constants be of type "const char *" instead of "char *". -Werror Abort compilation if warnings are issued. -Wall Activate all warnings, except -Werror, -Wunusupported and -Wwrite-strings. Linker options: -Ldir Specify an additional static library path for the -l option. The default library paths are /usr/local/lib, /usr/lib and /lib. -lxxx Link your program with dynamic library libxxx.so or static library libxxx.a. The library is searched in the paths specified by the -L option. -shared Generate a shared library instead of an executable. -soname name set name for shared library to be used at runtime -static Generate a statically linked executable (default is a shared linked executable). -rdynamic Export global symbols to the dynamic linker. It is useful when a library opened with "dlopen()" needs to access executable symbols. -r Generate an object file combining all input files. -Wl,-Ttext,address Set the start of the .text section to address. -Wl,--oformat,fmt Use fmt as output format. The supported output formats are: "elf32-i386" ELF output format (default) "binary" Binary image (only for executable output) "coff" COFF output format (only for executable output for TMS320C67xx target) -Wl,-rpath=path Set custom library search path Debugger options: -g Generate run time debug information so that you get clear run time error messages: " test.c:68: in function 'test5()': dereferencing invalid pointer" instead of the laconic "Segmentation fault". -b Generate additional support code to check memory allocations and array/pointer bounds. -g is implied. Note that the generated code is slower and bigger in this case. Note: -b is only available on i386 for the moment. -bt N Display N callers in stack traces. This is useful with -g or -b. Note: GCC options -Ox, -fx and -mx are ignored. SEE ALSO
gcc(1) AUTHOR
Fabrice Bellard 2012-07-21 TCC(1)
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