C语言库函数手册--c语言大全

函数名: abort 功 能: 异常终止一个进程 用 法: void abort(void); 程序例: #include #include int main(void) { printf("Calling abort()\n"); abort(); return 0; /* This is never reached */ } 函数名: abs 功 能: 求整数的绝对值 用 法: int abs(int i); 程序例: #include #include int main(void) { int number = -1234; printf("number: %d absolute value: %d\n", number, abs(number)); return 0; } 函数名: absread, abswirte 功 能: 绝对磁盘扇区读、写数据 用 法: int absread(int drive, int nsects, int sectno, void *buffer); int abswrite(int drive, int nsects, in tsectno, void *buffer); 程序例: /* absread example */ #include #include #include #include int main(void) { int i, strt, ch_out, sector; char buf[512]; printf("Insert a diskette into drive A and press any key\n"); getch(); sector = 0; if (absread(0, 1, sector, &buf) != 0) { perror("Disk problem"); exit(1); } printf("Read OK\n"); strt = 3; for (i=0; i<80; i++) { ch_out = buf[strt+i]; putchar(ch_out); } printf("\n"); return(0); } 函数名: access 功 能: 确定文件的访问权限 用 法: int access(const char *filename, int amode); 程序例: #include #include int file_exists(char *filename); int main(void) { printf("Does NOTEXIST.FIL exist: %s\n", file_exists("NOTEXISTS.FIL") ? "YES" : "NO"); return 0; } int file_exists(char *filename) { return (access(filename, 0) == 0); } 函数名: acos 功 能: 反余弦函数 用 法: double acos(double x); 程序例: #include #include int main(void) { double result; double x = 0.5; result = acos(x); printf("The arc cosine of %lf is %lf\n", x, result); return 0; } 函数名: allocmem 功 能: 分配DOS存储段 用 法: int allocmem(unsigned size, unsigned *seg); 程序例: #include #include #include int main(void) { unsigned int size, segp; int stat; size = 64; /* (64 x 16) = 1024 bytes */ stat = allocmem(size, &segp); if (stat == -1) printf("Allocated memory at segment: %x