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Chapter 1 LabWindows/CVI Compiler
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National Instruments Corporation 1-5 LabWindows/CVI Programmer Reference Manual
You can set the maximum alignment as follows:
#pragma pack(4) /* sets maximum alignment to 4 bytes */
#pragma pack(8) /* sets maximum alignment to 8 bytes */
#pragma pack() /* resets to the default*/
The maximum alignment the compiler applies to a structure is based on the last pack
pragma
statement it sees before the definition of the structure.
Program Entry Points (Windows 95/NT Only)
Under Windows 95/NT, you can use WinMain instead of main as the entry-point function to
your program. You might want to do this if you plan to link your executable using an external
compiler. You must include
windows.h for the data types that normally appear in the
WinMain parameter list. The following is the prototype for WinMain with the Windows data
types reduced to intrinsic C types.
int __stdcall WinMain(void * hInstance, void * hPrevInstance,
char * lpszCmdLine int nCmdShow)
C Library Issues
This section discusses special considerations in LabWindows/CVI in the areas of low-level
I/O functions and the UNIX C library.
Using the Low-Level I/O Functions
Many functions in the UNIX libraries and the C compiler libraries for the PC are not ANSI C
Standard Library functions. In general, LabWindows/CVI implements the ANSI C Standard
Library. Under UNIX, you can call UNIX libraries for the non-ANSI C functions in
conjunction with LabWindows/CVI.
The low-level I/O functions
open, close, read, write, lseek, and eof are not in the
ANSI C Standard Library. Under UNIX, these functions are available in the UNIX C library.
Refer to Chapter 5, UNIX Compiler/Linker Issues, for more information.
Under Windows, you can use these functions along with
sopen and fdopen if you include
lowlvlio.h.
00ProRef.book : 06chap01.fm Page 5 Monday, March 9, 1998 3:23 PM