In C, “strings” are just plain char arrays. Therefore, you can’t directly concatenate them with other “strings”. You can use the strcat function, which appends the string pointed to by src to the end of the string pointed to by dest: char *strcat(char *dest, const char *src); Here is an example from cplusplus.com: char str[80]; … Read more
You can try this: NSLog(@”%@”, NSStringFromCGPoint(cgPoint)); There are a number of functions provided by UIKit that convert the various CG structs into NSStrings. The reason it doesn’t work is because %@ signifies an object. A CGPoint is a C struct (and so are CGRects and CGSizes).
If you set LD_PRELOAD to the path of a shared object, that file will be loaded before any other library (including the C runtime, libc.so). So to run ls with your special malloc() implementation, do this: $ LD_PRELOAD=/path/to/my/malloc.so /bin/ls
%lu is the correct format for unsigned long. Sounds like there are other issues at play here, such as memory corruption or an uninitialized variable. Perhaps show us a larger picture?
Use the ll (el-el) long-long modifier with the u (unsigned) conversion. (Works in windows, GNU). printf(“%llu”, 285212672);
You need to seek to the end of the file and then ask for the position: fseek(fp, 0L, SEEK_END); sz = ftell(fp); You can then seek back, e.g.: fseek(fp, 0L, SEEK_SET); or (if seeking to go to the beginning) rewind(fp);
Wow, this requirement goes way back to the 1970s. In the very early days of pre-standardised C, if you wanted to invoke the preprocessor, then you had to write a # as the first thing in the first line of a source file. Writing only a # at the top of the file affords flexibility … Read more
The languages have similar feature-sets. The performance difference comes from the fact that Fortran says aliasing is not allowed, unless an EQUIVALENCE statement is used. Any code that has aliasing is not valid Fortran, but it is up to the programmer and not the compiler to detect these errors. Thus Fortran compilers ignore possible aliasing … Read more
With a union, you’re only supposed to use one of the elements, because they’re all stored at the same spot. This makes it useful when you want to store something that could be one of several types. A struct, on the other hand, has a separate memory location for each of its elements and they … Read more
Original answer { void *mem = malloc(1024+16); void *ptr = ((char *)mem+16) & ~ 0x0F; memset_16aligned(ptr, 0, 1024); free(mem); } Fixed answer { void *mem = malloc(1024+15); void *ptr = ((uintptr_t)mem+15) & ~ (uintptr_t)0x0F; memset_16aligned(ptr, 0, 1024); free(mem); } Explanation as requested The first step is to allocate enough spare space, just in case. Since … Read more