fputs

问题 I'm trying to do random write (Benchmark test) to a file using multiple threads (pthread). Looks like if I comment out mutex lock the created file size is less than actual as if Some writes are getting lost (always in some multiple of chunk size). But if I keep the mutex it's always exact size. Is my code have a problem in other place and mutex is not really required (as suggested by @evan ) or mutex is necessary here void *DiskWorker(void *threadarg) { FILE *theFile = fopen(fileToWrite, "a+"

问题 I've been having trouble with fputs lately: when printing some strings in a text file with fputs, it happens I get other characters than A-Z, a-z, 0-9 in (chars that aren't part of the string). I made absolutely sure the strings all end with the null character. Unfortunately I can't give you more information, since I did not personally test the program, that was the feedback I received. But after I replaced fputs with fprintf it worked properly. So my question is: is fputs sort of dangerous?

问题 I'm doing an insertion, that imply a file , a string , and a new file who will receive all the data of the original file plus the string to be inserted , and it will replace the original file. So, for example, my original file: data.txt line1 line2 line3 line4 line5 will become, with the insertion of the string "newline": data_temp.txt --> renamed later data.txt line1 line2 line3 line4 line5 newline With that purpose, I have the following code: /* FILE variables of the original file and the

问题 I wanted to read input from user (multiple lines) and write it into a file using fputs(). Here is my code #include<stdio.h> #include<stdlib.h> int main() { FILE *fp; char s[25]; fp=fopen("myname","w"); if(fp==NULL) { perror("Error opening file\n"); exit(1); } while(fgets(s,25,stdin)!=NULL) fputs(s,fp); fclose(fp); return 0; } After getting input from user, i am using Ctrl+C to close the input prompt of the program (I'm using linux). Then if i open the file, it contains nothing. How could I

问题 In the computer lab at school we wrote a program using fputs and the compiler returned an error gets is a dangerous function to use and a similar error for fputs but at home when i type in this bit of code: #include <stdio.h> main() { FILE *fp; char name[20]; fp = fopen("name.txt","w"); gets(name); fputs(name,fp); fclose(fp); } i get no errors what so ever. The one at school was similar to this one, just a bit lengthy and having more variables. I use codeblocks at home and the default gcc

问题 Here is my current problem: I am trying to create a file of x MB in C++. The user will enter in the file name then enter in a number between 5 and 10 for the size of the file they want created. Later on in this project i'm gonna do other things with it but I'm stuck on the first step of creating the darn thing. My problem code (so far): char empty[1024]; for(int i = 0; i < 1024; i++) { empty[i] = 0; } fileSystem = fopen(argv[1], "w+"); for(int i = 0; i < 1024*fileSize; i++){ int temp = fputs

问题 The exercise is simple. The father process lets me write my name and surname in a file. The son process waits 5 seconds, then reads and displays it. I can't use the #wait() function. #include <cstdlib> #include <stdio.h> #include <string.h> #include <stdlib.h> #include <unistd.h> int main(int argc, char** argv) { char name[20]; char surname[20]; char outp[50]; // The file pointer FILE *file; // Open the file in write mode file = fopen("dati.txt", "w+"); pid_t pid; pid=fork(); if(pid>0){

问题 I read this concept from book that when we attemp to write \n to the file using fputs(), fputs() converts the \n to \r\n combination and then if we read the same line back using fgets () the reverse conversion happens means \r\n back convert to \n. I don't get that what is the purpose behind this? 回答1: It is because Windows (and MS-DOS) text files are supposed to have lines ending in \r\n, and portable C programs are supposed to simply use \n because C was originally defined on Unix. And it's

问题 I need to put out a double value into an file. So for all my other string i have to put out i use fputs because i think and timed it that fputs is faster then fprintf. But if i want to put out the double value i can't do this with fputs so i tried fprintf. This is very slow. I need more time if i replace the fprintf and puts there an fputs("TEST",file); How can i put out the double as fast as the string. Need i to convert it first to string? I found some conversion. But if i use them i am as

问题 I don't get it why fputs and fprintf reverse stream order. int fputs (const char * str, FILE * stream); int fprintf (FILE * stream, const char * format, ...); ssize_t write(int fd, const void *buf, size_t count); I known fprintf put stream in forward to support variable arguments,But why fputs series don't keep consistency ??? 回答1: Because these things were written many decades ago, it's generally only be a question of interest for historians :-) It was probably just a design decision (or