以下来自长串C ++源代码和头文件的片段（我将很乐意在需要时分享）显示用户定义的函数（或对象？）Read被调用为正在进行的多线程操作的一部分。
作为识别问题的一部分，我在调用函数之前和之后打印了标志：
std::cout<<"Before calling\n";
和
std::cout<<"After calling\n";
我还在调用函数后插入了要打印的标志：
std::cout<<"Entered the function";
整个应用程序完美编译并且运行顺畅 - 直到调用此函数 Read ，它才会被执行。
在输出中，您会看到“在通话前”和“通话后”，但从不会出现“已输入的功能”。
使用的操作系统是Ubuntu 16.04，带有g ++编译器。
截至目前，我只分享了与问题相关的两个片段 - （因为单个文件大约有1500行代码;我认为它应该足够了，如果不是，请告诉我）
以下是线程的片段，其中函数被称为（在第130行），然后是定义函数的另一个文件。
调用Function的线程：
1 void* StartGenericReadThread(void *ThreadAr)
2 { //std::cout<<"flag GenericThread\n";
3 //printf("\nSuccess");
4 int PORT = ((ThreadArg*)ThreadAr)->PORT;
5 #ifdef WIN32
6 Sleep(4000);
7 #else
8 sleep(4);
9 #endif
10 DSDMux *Mux;
11 DSDConfigReader *cfg;
12 SNMPTrap Trap;
13 DSDMessageSender *DMS;
14 Mux = ((ThreadArg*)ThreadAr)->Mux;
15 cfg = ((ThreadArg*)ThreadAr)->cfg;
16 DMS = ((ThreadArg*)ThreadAr)->MSG;
17
18
19 strcpy(DMS->SNMP_DET.DSD_MAN_IP,cfg->DSDSetting.DSD_MANAGER_IP);
20 strcpy(DMS->SNMP_DET.SNMP_MAN_IP,cfg->DSDSetting.SNMP_TRAP_IP);
21 DMS->SNMP_DET.SNMP_MAN_PORT = cfg->DSDSetting.SNMP_TRAP_PORT;
22 DMS->SNMP_DET.DSD_MAN_PORT = 162;
23
24 if ( checkflag != 1) //EDITED
25 {std::cout<<"\nDSD Manager IP set to
26 "<<cfg->DSDSetting.DSD_MANAGER_IP<<"\n";
27 std::cout<<"SNMP TRAP IP set to
28 "<<cfg->DSDSetting.SNMP_TRAP_IP<<"\n";
29
30 std::cout<<"SNMP TRAP PORT set to "<<cfg->DSDSetting.SNMP_TRAP_PORT<<"\n";
31 checkflag=1;
32 }
33
34 try
35 { //std::cout<<"Entered try\n";
36 bool IPLostErrSet(false),IPGainset(false),FIFOreaderr(false);
37 //DSDCo
38 int nStatus, nLatched,inFifoLoad,MaxBuffRead,lostCount(0);
39 dr = theInput[PORT].SetRxControl(DTAPI_RXCTRL_RCV);
40
41 if ( DTAPI_OK != dr )
42 { //std::cout<<"\nSetRXControl is not OK";
43 // return NULL; EDITED
44 }
45
46 #ifdef WIN32
47 while(!_kbhit())
48 #else
49 while(1)
50 #endif
51 { //EDITED
52 //MaxBuffRead=(inFifoLoad/188)*188;
53 //int DmaSize = ( inFifoLoad > c_ReadBufferSize ) ? c_ReadBufferSize : MaxBuffRead;
54
55 theInput[PORT].GetFlags(nStatus, nLatched);
56 if ( 0 != (DTAPI_RX_FIFO_OVF & nLatched) )
57 {
58 printf("Fifo overflow for input port %d\t\t\t\t\t[Error]\n",PORT+1);
59 DMS->SendLog(FIFO_OVERFLOW,PORT+1);
60 theInput[PORT].ClearFifo();
61 dr = theInput[PORT].SetRxControl(DTAPI_RXCTRL_RCV);
62 if ( DTAPI_OK != dr )
63 {
64 printf("\nError");
65
66 }
67 else
68 DMS->SendLog(FIFO_OVERFLOW_CLR,PORT+1);
69 }
70 theInput[PORT].GetFifoLoad(inFifoLoad);
71 inFifoLoad = MINBUFFSIZE + 512;
72 if (inFifoLoad < MINBUFFSIZE+512)
73 {
74 lostCount++;
75 if(lostCount>1000&&!IPLostErrSet)
76 {
77 lostCount=0;
78 printf("\nInput lost on port %d\t\t\t\t\t\t[ERROR]",PORT+1);
79
80 DMS->SendLog(INPUT_LOST,PORT+1);
81 int pid;
82 /*for(pid=21;pid<8191;pid++)
83 {
84 if(cfg->MuxCfg.PORT[PORT].PID[pid].Mux)
85 DMS->SendLog(PID_REMUX_ERR,pid,PORT+1);
86 }*/
87 Mux->PSI.PATdata.Table[PORT].Section[0].no_of_programs = 0;
88 IPGainset = false;
89 IPLostErrSet = true;
90 }
91
92 #ifdef WIN32
93 Sleep(1);
94 #else
95 usleep(1000);
96 #endif
97 continue;
98 }
99 lostCount = 0;
100 //std::cout<<"\nWill check for IPGAINSET now\n";
101 if(!IPGainset)
102 { //std::cout<<"IPGAINSET IS FALSE\n";
103 cfg->OutputConf.Status=true;
104 printf("\nInput signal detected on port %d\t\t\t\t\t[ OK ]",PORT+1);
105
106 DMS->SendLog(INPUT_GAIN,PORT+1);
107 /*int pid;
108 for(pid=21;pid<8191;pid++)
109 {
110 if(cfg->MuxCfg.PORT[PORT].PID[pid].Mux)
111 {
112 //std::cout<<pid;
113 DMS->SendLog(PID_REMUX,pid,PORT+1);
114 }
115 };*/
116 IPLostErrSet = false;
117 IPGainset = true;
118 }
119 //std::cout<<"IPGAINSET is TRUE\n";
120 //printf("\t%d",inFifoLoad);
121 MaxBuffRead=(inFifoLoad/188)*188;
122 int DmaSize = ( inFifoLoad > c_ReadBufferSize ) ? c_ReadBufferSize : MaxBuffRead;
123
124 // fifold=(int)DmaSize;
125 // char data[65424*10];
126
127
128 std::cout<<"Before Calling\n";
129
130 dr = theInput[PORT].Read(Mux->TSPacket[PORT].data,DmaSize);
131
132 std::cout<<"After Calling\n";
133
134 if ( DTAPI_OK != dr )
135 {// std::cout<<"Error in executing Read function\n";
136 if(!FIFOreaderr)
137 DMS->SendLog(FIFO_READ_ERR,dr,PORT+1);
138
139 }
140 else
141 {
142 Mux->ParseAndMuxTS(PORT,DmaSize,cfg,fs);
143
144 }
145 }
146 return NULL;
147
148 }
149 catch(...)
150 {
151 // printf("Error in StartGenericReadThread\n");
152 DMS->SendLog(INTERNAL_ERR,0,0,0,"StartGenericReadThread");
153 return NULL;
154 }
155 }
现在，以下是函数定义的片段（在另一个文件中）：
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include "DTAPI.h"
#include "DtapiUtility.h"
#include "Dta1xxIoCtl.h"
#include "Dta1xxCodes.h"
#include "Dtu2xxIoCtl.h"
#include "Dtu2xxCodes.h"
#include <iostream>
//+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ TsInpChannel implementation +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
//.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- TsInpChannel::Read -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
//
// Read data bytes from the input channel using DMA transfers.
//
DTAPI_RESULT TsInpChannel::Read(
char* pBuffer, // [in] Pointer to data to be read from Device
int NumBytesToRead) // [in] Number of bytes to be read from Device
{
std::cout<<"Entered the function\n";
// Must be attached.
//if (!m_Attached) EDITED
// return DTAPI_E_NOT_ATTACHED; EDITED
// Validity check on parameters
if (NumBytesToRead<0 || NumBytesToRead%4!=0)
return DTAPI_E_INVALID_SIZE;
if ((atoi)(pBuffer)%4 != 0)
return DTAPI_E_INVALID_BUF;
// Avoid strange effects when NumBytesToRead is zero
if (NumBytesToRead == 0)
return DTAPI_OK;
DTAPI_RESULT dr;
// Processing is dependent on device category
if (m_HwFuncDesc.m_DvcDesc.m_Category == DTAPI_CAT_PCI) {
//-.-.-.-.-.-.-.-.-.- Call the appropiate device IoCtl handler -.-.-.-.-.-.-.-.-.-
DTA1XX_IOCTL_DATA iod;
memset(&iod, 0, sizeof(DTA1XX_IOCTL_DATA));
iod.m_nChIdx = GetIndexOnDevice();
iod.m_Data.m_DataTransDesc.m_pBuffer = pBuffer;
iod.m_Data.m_DataTransDesc.m_nNumBytesToTr = NumBytesToRead;
dr = ioctl(m_fdDevice, DTA1XX_IOCTL_DMA_USERMEM_READ, &iod);
if ( dr != DTAPI_OK )
return dr;
}
else if (Category() == DTAPI_CAT_USB) {
// Read using file IO
int ret = read(m_fdDevice, pBuffer, NumBytesToRead);
if ( ret < 0 )
return DTAPI_E_DEV_DRIVER;
}
else //EDITED
{ std::cout<<"\n Beginning to read file at /home/rtpl/Desktop/ts.mp4";
char * storedfilepath = "/home/rtpl/Desktop/ts.mp4";
int *vedant = open(storedfilepath,O_RDONLY);
int ret = read(vedant, pBuffer, NumBytestoRead);
if ( ret < 0)
std::cout<<"\n File contents cannot be read";
//return DTAPI_E_INTERNAL; // Unknown device category
}
return DTAPI_OK;
}
//.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- TsInpChannel::ReadDirect -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-
//
DTAPI_RESULT TsInpChannel::ReadDirect(
char* pBuffer, // [in] Buffer to store data
int NumBytesToRead, // [in] Number of bytes to be read
int& NumBytesRead) // [out] Number of bytes read
{
return DTAPI_E_NOT_SUPPORTED;
}
//-.-.-.-.-.-.-.-.-.-.-.-.-.-.- TsInpChannel::ReadUsingDma -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.
//
// Old name of Read. Still here for backward compatibility.
//
DTAPI_RESULT TsInpChannel::ReadUsingDma(
char* pBuffer, // [in] Buffer to store data
int NumBytesToRead) // [in] Number of bytes to be written to PCI card
{
return Read(pBuffer, NumBytesToRead);
}