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Full Discussion: Pointer and address
Top Forums Programming Pointer and address Post 302803877 by DGPickett on Tuesday 7th of May 2013 03:24:49 PM
Old 05-07-2013
argv is an array of pointers to arrays of char, so first think of it at char**, something that needs one dereferencing ( * or [#] ) to get to char*, which C uses as string. The actual rules for argv is that the last element is a null pointer, so you can size it somewhat analagous to strlen(). The argc is just for your convenience, provided by the loader. char** could be char[][] which is a 2 dimensional heap of characters locally, but the name would still need dereferencing. Since printf's '%s' demands a char*, one layer of dereferencing is right. Another way to think of '*' is '[0]', so **argv is the first char of argv[0], is argv[0][0]. Array names are of type type* even if the array is local, but local arrays have size of the array not size of a pointer. So, 'char *x = "Y" ;' is a local pointer variable initialized with a pointer size 4 to a constant string, two hunks of storage, but 'char x[] = "Y" ;' is a local array size 2 of characters Y and null (sized implicitly by the initializer), one small hunk of storage, and there is no pointer storage, just an array name that is always a pointer.

Last edited by DGPickett; 05-07-2013 at 04:35 PM..
 

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QD-CONFIGG(1)															     QD-CONFIGG(1)

NAME
qd-config - determine flags for compilation and linking SYNOPSIS
qd-config [options] DESCRIPTION
To link a Fortran-90 program with the C++ qd library, it is recommended to link with the C++ compiler used to generate the library. The Fortran 90 interface (along with a C-style main function calling f_main) is found in the qdmod library. The qd-config script can be used to determine which flags to pass to compile and link your programs. OPTIONS
--src Switch between source and system location. --prefix Output configured prefix value. --exec-prefix Output configured exec_prefix value. --build-flags Compiler options used during build. --build-libs Linker options used during build. --configure-args Configure arguments used for build. --cxx C++ compiler. --cflags C++ preprocessor and compiler options. --cxxflags C++ compiler options. --libs-la C++ linker options and libtool archive location. --libs C++ linker options. --fc Fortran compiler. --fcflags Fortran compiler options. --fclibs Fortran linker options. --fmainlib C++ linker options for main program written in Fortran. --version Output version. AUTHOR
This manual page was written by Daniel Leidert <daniel.leidert@wgdd.de> for the Debian project (but may be used by others). User Commands 2008-05-11 QD-CONFIGG(1)
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