c

问题 I have a code uses Cairo and Pango to create an image : #include<stdio.h> #include<cairo.h> #include<pango/pangocairo.h> #define IMAGE_WIDTH 650 #define IMAGE_HEIGHT 150 #define TEXT "HELLO WORLD" #define FONT "MizuFontAlphabet Normal 40" /* * $ gcc $(pkg-config pangocairo cairo --cflags --libs) file.c */ int main(int argc , char** argv) { cairo_surface_t *surface; cairo_t *cr; PangoLayout *layout; PangoFontDescription *desc; PangoRectangle extents; surface = cairo_image_surface_create(CAIRO

问题 I am not sure why htons and ntohs both exist in the standard library. They do exactly the same thing -- unless I'm confused somehow! The same goes for htonl and ntohl . 回答1: They make for self-documenting code that tells the reader whether the data is in host- or network- order. 回答2: This is in case a machine has some sort of unusual endianness besides big-endian or little-endian that isn't one or more simple byte swaps. For example, if the value 0x0A0B0C0D was represented internally as 0B 0C

问题 I am not sure why htons and ntohs both exist in the standard library. They do exactly the same thing -- unless I'm confused somehow! The same goes for htonl and ntohl . 回答1: They make for self-documenting code that tells the reader whether the data is in host- or network- order. 回答2: This is in case a machine has some sort of unusual endianness besides big-endian or little-endian that isn't one or more simple byte swaps. For example, if the value 0x0A0B0C0D was represented internally as 0B 0C

问题 For purposes expressed in this question, we want to do this: typedef struct { int a; } A; typedef struct { struct { int a; }; int b; } B; A *BToA(B *b) { return (A *) b; } B *AToB(A *a) { return (B *) a; } The desire is that the casts conform to C 2011 6.7.2.1 15, which says “A pointer to a structure object, suitably converted, points to its initial member (or if that member is a bit-field, then to the unit in which it resides), and vice versa.” Since the struct { int a; } inside B does not

问题 Using bitwise operator how can I test if the n least significant bits of an integer are either all sets or all not sets. For example if n = 3 I only care about the 3 least significant bits the test should return true for 0 and 7 and false for all other values between 0 and 7. Of course I could do if x = 0 or x = 7 , but I would prefer something using bitwise operators. Bonus points if the technique can be adapted to take into accounts all the bits defined by a mask. Clarification : If I

问题 I am unable to find in the C standard docs specifically where it says that multidimensional arrays are contiguous. While it can be inferred from the fact that array elements are contiguous, I want some perspective from the community. The following code prints out the numbers in the order that I would expect, which is 1 - 9. #include <stdio.h> int main() { int a[][3] = {{1,2,3},{4,5,6},{7,8,9}}; int* p = (int*)a; int i; for (i = 0; i < sizeof(a)/sizeof(int); i++) printf("%d ",p[i]); return 0;

问题 How can i strip the HTML from document between and including the <...> tags in a HTML document using C? My current program uses curl to get the contents of the webpage and puts it into a text file, it then reads from the text file and removes the <>, but i am unsure of how to remove everything between those tags. #include <curl/curl.h> #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #define WEBPAGE_URL "http://homepages.paradise.net.nz/adrianfu/index.html"

问题 How can i strip the HTML from document between and including the <...> tags in a HTML document using C? My current program uses curl to get the contents of the webpage and puts it into a text file, it then reads from the text file and removes the <>, but i am unsure of how to remove everything between those tags. #include <curl/curl.h> #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #define WEBPAGE_URL "http://homepages.paradise.net.nz/adrianfu/index.html"

问题 I have a dataset, made up of a mask file, and a data file. the mask file tells the decoder whether there are 8 bits per field present, or 4, for the current offset of the datafile. I need to shift the data out according to the mask, and write the decoded file, with all 8 bits per field. I'm trying to accomplish this in C. void shift_4bits_left(unsigned char* array, unsigned short size) { int i; unsigned char shifted = 0x00; unsigned char overflow = (0xF0 & array[0]) >> 4; for (i = (size - 1);

问题 I have a dataset, made up of a mask file, and a data file. the mask file tells the decoder whether there are 8 bits per field present, or 4, for the current offset of the datafile. I need to shift the data out according to the mask, and write the decoded file, with all 8 bits per field. I'm trying to accomplish this in C. void shift_4bits_left(unsigned char* array, unsigned short size) { int i; unsigned char shifted = 0x00; unsigned char overflow = (0xF0 & array[0]) >> 4; for (i = (size - 1);