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Full Discussion: C header file and extern
Top Forums Programming C header file and extern Post 302851825 by tornow on Monday 9th of September 2013 06:46:08 PM
Old 09-09-2013
Thanks so much, it seems clear now. I got another question about header files. Say i got checkr.h with:
Code:
void check_argc(int, int);

and the function in checkr.c:
Code:
 void check_argc(int argcount, int n) {         if ( argcount != n ) {                 fprintf(stderr, "ERROR: wrong argument count\n");                 usage();                 exit(EXIT_FAILURE);         } }

From what you say i think i would need to use "extern" in checkr.h ? Can i also use it in the main file (called server.c) ? I know that i don't have to, but it helps me a bit to keep track of the functions without opening and closing files all the time (or using :vsplit). I think it has to do with definition and declaration? I read about it quite often, but never really understand it and usually forget it soon.
 

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pods::SDL::GFX::ImageFilter(3pm)			User Contributed Perl Documentation			  pods::SDL::GFX::ImageFilter(3pm)

NAME
SDL::GFX::ImageFilter - image filtering functions CATEGORY
TODO, GFX METHODS
MMX_detect int gfx_image_MMX_detect() CODE: SDL_imageFilterMMXdetect(); MMX_off void gfx_image_MMX_off() CODE: SDL_imageFilterMMXoff(); MMX_on void gfx_image_MMX_on() CODE: SDL_imageFilterMMXon(); add int gfx_image_add(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterAdd(Src1, Src2, Dest, length); OUTPUT: RETVAL mean int gfx_image_mean(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterMean(Src1, Src2, Dest, length); OUTPUT: RETVAL sub int gfx_image_sub(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterSub(Src1, Src2, Dest, length); OUTPUT: RETVAL abs_diff int gfx_image_abs_diff(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterAbsDiff(Src1, Src2, Dest, length); OUTPUT: RETVAL mult int gfx_image_mult(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterMult(Src1, Src2, Dest, length); OUTPUT: RETVAL mult_nor int gfx_image_mult_nor(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterMultNor(Src1, Src2, Dest, length); OUTPUT: RETVAL mult_div_by_2 int gfx_image_mult_div_by_2(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterMultDivby2(Src1, Src2, Dest, length); OUTPUT: RETVAL mult_div_by_4 int gfx_image_mult_div_by_4(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterMultDivby4(Src1, Src2, Dest, length); OUTPUT: RETVAL bit_and int gfx_image_bit_and(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterBitAnd(Src1, Src2, Dest, length); OUTPUT: RETVAL bit_or int gfx_image_bit_or(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterBitOr(Src1, Src2, Dest, length); OUTPUT: RETVAL div int gfx_image_div(Src1, Src2, Dest, length) unsigned char *Src1 unsigned char *Src2 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterDiv(Src1, Src2, Dest, length); OUTPUT: RETVAL bit_negation int gfx_image_bit_negation(Src1, Dest, length) unsigned char *Src1 unsigned char *Dest int length CODE: RETVAL = SDL_imageFilterBitNegation(Src1, Dest, length); OUTPUT: RETVAL add_byte int gfx_image_add_byte(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned char C CODE: RETVAL = SDL_imageFilterAddByte(Src1, Dest, length, C); OUTPUT: RETVAL add_uint int gfx_image_add_uint(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned int C CODE: RETVAL = SDL_imageFilterAddUint(Src1, Dest, length, C); OUTPUT: RETVAL add_byte_to_half int gfx_image_add_byte_to_half(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned char C CODE: RETVAL = SDL_imageFilterAddByteToHalf(Src1, Dest, length, C); OUTPUT: RETVAL sub_byte int gfx_image_sub_byte(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned char C CODE: RETVAL = SDL_imageFilterSubByte(Src1, Dest, length, C); OUTPUT: RETVAL sub_uint int gfx_image_sub_uint(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned int C CODE: RETVAL = SDL_imageFilterSubUint(Src1, Dest, length, C); OUTPUT: RETVAL shift_right int gfx_image_shift_right(Src1, Dest, length, N) unsigned char *Src1 unsigned char *Dest int length unsigned char N CODE: RETVAL = SDL_imageFilterShiftRight(Src1, Dest, length, N); OUTPUT: RETVAL shift_right_uint int gfx_image_shift_right_uint(Src1, Dest, length, N) unsigned char *Src1 unsigned char *Dest int length unsigned char N CODE: RETVAL = SDL_imageFilterShiftRightUint(Src1, Dest, length, N); OUTPUT: RETVAL mult_by_byte int gfx_image_mult_by_byte(Src1, Dest, length, C) unsigned char *Src1 unsigned char *Dest int length unsigned char C CODE: RETVAL = SDL_imageFilterMultByByte(Src1, Dest, length, C); OUTPUT: RETVAL shift_right_and_mult_by_byte int gfx_image_shift_right_and_mult_by_byte(Src1, Dest, length, N, C) unsigned char *Src1 unsigned char *Dest int length unsigned char N unsigned char C CODE: RETVAL = SDL_imageFilterShiftRightAndMultByByte(Src1, Dest, length, N, C); OUTPUT: RETVAL shift_left_byte int gfx_image_shift_left_byte(Src1, Dest, length, N) unsigned char *Src1 unsigned char *Dest int length unsigned char N CODE: RETVAL = SDL_imageFilterShiftLeftByte(Src1, Dest, length, N); OUTPUT: RETVAL shift_left_uint int gfx_image_shift_left_uint(Src1, Dest, length, N) unsigned char *Src1 unsigned char *Dest int length unsigned char N CODE: RETVAL = SDL_imageFilterShiftLeftUint(Src1, Dest, length, N); OUTPUT: RETVAL shift_left int gfx_image_shift_left(Src1, Dest, length, N) unsigned char *Src1 unsigned char *Dest int length unsigned char N CODE: RETVAL = SDL_imageFilterShiftLeft(Src1, Dest, length, N); OUTPUT: RETVAL binarize_using_threshold int gfx_image_binarize_using_threshold(Src1, Dest, length, T) unsigned char *Src1 unsigned char *Dest int length unsigned char T CODE: RETVAL = SDL_imageFilterBinarizeUsingThreshold(Src1, Dest, length, T); OUTPUT: RETVAL clip_to_range int gfx_image_clip_to_range(Src1, Dest, length, Tmin, Tmax) unsigned char *Src1 unsigned char *Dest int length unsigned char Tmin unsigned char Tmax CODE: RETVAL = SDL_imageFilterClipToRange(Src1, Dest, length, Tmin, Tmax); OUTPUT: RETVAL normalize_linear int gfx_image_normalize_linear(Src1, Dest, length, Cmin, Cmax, Nmin, Nmax) unsigned char *Src1 unsigned char *Dest int length int Cmin int Cmax int Nmin int Nmax CODE: RETVAL = SDL_imageFilterNormalizeLinear(Src1, Dest, length, Cmin, Cmax, Nmin, Nmax); OUTPUT: RETVAL convolve_kernel_3x3_divide int gfx_image_convolve_kernel_3x3_divide(Src, Dest, rows, columns, Kernel, Divisor) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char Divisor CODE: RETVAL = SDL_imageFilterConvolveKernel3x3Divide(Src, Dest, rows, columns, Kernel, Divisor); OUTPUT: RETVAL convolve_kernel_5x5_divide int gfx_image_convolve_kernel_5x5_divide(Src, Dest, rows, columns, Kernel, Divisor) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char Divisor CODE: RETVAL = SDL_imageFilterConvolveKernel5x5Divide(Src, Dest, rows, columns, Kernel, Divisor); OUTPUT: RETVAL convolve_kernel_7x7_divide int gfx_image_convolve_kernel_7x7_divide(Src, Dest, rows, columns, Kernel, Divisor) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char Divisor CODE: RETVAL = SDL_imageFilterConvolveKernel7x7Divide(Src, Dest, rows, columns, Kernel, Divisor); OUTPUT: RETVAL convolve_kernel_9x9_divide int gfx_image_convolve_kernel_9x9_divide(Src, Dest, rows, columns, Kernel, Divisor) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char Divisor CODE: RETVAL = SDL_imageFilterConvolveKernel9x9Divide(Src, Dest, rows, columns, Kernel, Divisor); OUTPUT: RETVAL convolve_kernel_3x3_shift_right int gfx_image_convolve_kernel_3x3_shift_right(Src, Dest, rows, columns, Kernel, NRightShift) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char NRightShift CODE: RETVAL = SDL_imageFilterConvolveKernel3x3ShiftRight(Src, Dest, rows, columns, Kernel, NRightShift); OUTPUT: RETVAL convolve_kernel_5x5_shift_right int gfx_image_convolve_kernel_5x5_shift_right(Src, Dest, rows, columns, Kernel, NRightShift) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char NRightShift CODE: RETVAL = SDL_imageFilterConvolveKernel5x5ShiftRight(Src, Dest, rows, columns, Kernel, NRightShift); OUTPUT: RETVAL convolve_kernel_7x7_shift_right int gfx_image_convolve_kernel_7x7_shift_right(Src, Dest, rows, columns, Kernel, NRightShift) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char NRightShift CODE: RETVAL = SDL_imageFilterConvolveKernel7x7ShiftRight(Src, Dest, rows, columns, Kernel, NRightShift); OUTPUT: RETVAL convolve_kernel_9x9_shift_right int gfx_image_convolve_kernel_9x9_shift_right(Src, Dest, rows, columns, Kernel, NRightShift) unsigned char *Src unsigned char *Dest int rows int columns Sint16 *Kernel unsigned char NRightShift CODE: RETVAL = SDL_imageFilterConvolveKernel9x9ShiftRight(Src, Dest, rows, columns, Kernel, NRightShift); OUTPUT: RETVAL sobel_x int gfx_image_sobel_x(Src, Dest, rows, columns) unsigned char *Src unsigned char *Dest int rows int columns CODE: RETVAL = SDL_imageFilterSobelX(Src, Dest, rows, columns); OUTPUT: RETVAL sobel_x_shift_right int gfx_image_sobel_x_shift_right(Src, Dest, rows, columns, NRightShift) unsigned char *Src unsigned char *Dest int rows int columns unsigned char NRightShift CODE: RETVAL = SDL_imageFilterSobelXShiftRight(Src, Dest, rows, columns, NRightShift); OUTPUT: RETVAL align_stack void gfx_image_align_stack() CODE: SDL_imageFilterAlignStack(); restore_stack void gfx_image_restore_stack() CODE: SDL_imageFilterRestoreStack(); AUTHORS
See "AUTHORS" in SDL. perl v5.14.2 2012-05-28 pods::SDL::GFX::ImageFilter(3pm)
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