c - 写入两个不同的txt文件

Question

#include "aservelibs/aservelib.h"
#include <stdio.h>
#include <math.h>
#include <string.h>

FILE *textFilePointer;
FILE *textFilePointer2;


typedef struct
{
    int notes;
    int velocity;
}NoteData;


void notetofile (NoteData input, int seqlen, int reclayer);

int main()
{

    int count, count2, note, vel = 0;
    char choice = 'y';
    struct layers;
    int reclayer = 1;
    int playlayer = 1;
    char choice2 = 'y', choice3 = 'y';
    int seqlen = 16;
    NoteData input;




    printf("Welcome To Jonny Maguire's Midi record and playback application. Please Select one of the following options...\n\n");
    aserveSay("Welcome To Jonny Maguires Midi record and playback application. Please Select one of the following options");
    aserveSleep(8000);
    while(choice != 'x')
    {



        printf("r to Record\np to Playback\nx to exit the program\n");
        aserveSay("choose r, to record a sequence, p, to playback your recording. Or select x, at any time to exit the program");

        scanf(" %c", &choice);

        if(choice == 'r')
        {
            while(choice2 != 'n')
            {
                aserveSay("you have chosen to record, enter the no. of notes you wish to record");
                printf("You have chosen to record, enter the no. of notes you wish to record \n\n");
                scanf(" %d", &seqlen);
                printf("Please play %d notes", seqlen);



                    textFilePointer = fopen("recording1.txt", "w");

                    textFilePointer2 = fopen("recording2.txt", "w");



                if(textFilePointer == NULL or textFilePointer2 == NULL)
                {
                    printf("Error Opening File!");
                }
                else
                {



                    //Recording 16 note data into txt file

                    notetofile(input, seqlen, reclayer);
                    printf("Would you like to record another layer?");
                    scanf(" %c", &choice2);



                }
                reclayer++;
            }
        }
            else if (choice == 'p')
            {

                while(choice3 != 'n')
                {
                    //If P is selected, playback of the txt file
                    printf("which sequence would like to playback? 1, 2 or both (3)?");
                    scanf(" %d", &playlayer);


                        textFilePointer = fopen("recording1.txt", "r");

                       // textFilePointer2 = fopen("recording2.txt", "r");



                    if(textFilePointer == NULL)
                    {
                        printf("Error Opening File!");
                    }

                    //read until end of file and convert frequency
                    if (playlayer == 1)
                    {
                    while(!feof(textFilePointer))
                    {
                        float frequency;
                        float amplitude = vel/127.0;

                        fscanf(textFilePointer, " %d %d\n", &input.notes, &input.velocity);
                        printf(" %d %d\n\n", input.notes, input.velocity);

                        frequency = 440 * pow(2, (note-69) /12.0);

                        aserveOscillator(0, frequency, amplitude, 0);
                        aserveSleep(500);
                        aserveOscillator(0, 0, 0, 0);
                    }
                    }
                }
                fclose(textFilePointer);
                playlayer++;
            }
        }

    return 0;
}

//function to write notes to file
void notetofile(NoteData input, int seqlen, int reclayer)
{
    for (int count = 1; count <= seqlen;)
    {

        input.notes = aserveGetNote();
        input.velocity = aserveGetVelocity();



        //only note on messages are sent to file
        if(input.velocity > 0)
        {
            printf("reclayer = %d\n", reclayer);
            if(reclayer == 1)
            {
                printf("test");
              fprintf(textFilePointer, " %d %d\n", input.notes, input.velocity);
                fprintf(textFilePointer, "test");
            }
            else if(reclayer == 2)
            {
                fprintf(textFilePointer2, " %d %d\n", input.notes, input.velocity);

            }

            printf("%d %d\n", input.notes, input.velocity);
            count++;
        }
    }

}

该程序旨在读取 MIDI 音符，将其写入 txt 文件，然后从文件读入振荡器。fprintf 未写入“notestofile”函数中的文件。这可能是因为我同时打开了两个 textFilePointers 。

Answer 1

当您写入两个文件recording1.txt和recording2.txt时，您不会追加，因此每次您想要写入时这些文件都会重置。如果你想追加，你必须使用模式“a”(用于追加)而不是“w”。

当您编写这些文件时，两个文件描述符 textFilePointer和textFilePointer2永远不会关闭，并且缓冲区不会显式刷新，因此当进程处于事件状态时您看不到文件中的内容。调用fclose这些文件描述符将刷新代码中的写入缓冲区，如下所示:

            textFilePointer = fopen("recording1.txt", "w");
            textFilePointer2 = fopen("recording2.txt", "w");

            if(textFilePointer == NULL or textFilePointer2 == NULL)
            {
                printf("Error Opening File!");
            }
            else
            {
                //Recording 16 note data into txt file
                notetofile(input, seqlen, reclayer);
                printf("Would you like to record another layer?");
                scanf(" %c", &choice2);

                //Added fclose calls to opened files:
                fclose( textFilePointer );
                fclose( textFilePointer2 );
                //TODO Check both fclose return values
            }

如果不关闭文件，则可能是文件描述符泄漏，在大多数 Linux 系统上，最大打开文件数的限制设置为 1024，输入 ulimit -n来看看它。

您可以查看事件进程上打开的描述符，以查看 lsof 的泄漏。命令或通过列表 /proc/<pid>/fd目录。