Programming Junk
Here is some code that I have come up with over the years. Some of this stuff I lost serious hair over; some I just thought may be useful to others. I apologize for lack of documentation, but most of this stuff was eeked out under heavy deadline. If you really need something here & just can't figure out how to use it, throw me some mail & I'll try to help (time permitting, of course). Enjoy.
(By the way, you should always step through someone else's code before you unleash it on your project/machine. If you do happen to use any of these classes / functions without first testing them, you do so at your own risk. In no way will I be responsible for any damage, misfortune, shifting of tectonic plates, or anything else bad that may occur through the use of the code samples contained herein)
MFC / Win32
- CComboBoxEx: An extended ComboBox control that adds auto-completion & persistence (.cpp)(.h)
- CCopyFileThread: A class for performing a copy operation in its own thread (.cpp)(.h)
- CStatusBarEx: A class that displays a progress control in the status bar (.cpp)(.h)
- CFloatEdit: CEdit subclass that provides simple floating point math entry such as 15/16 + 2/3 (.cpp)(.h)
- CVersionInfo: Wrapper class that allows easy access to VERSIONINFO resources (.cpp)(.h)
- Create a new process & check if it has exited
- Check if an ODBC datasource exists, and add it if it doesn't
UNIX
- Determining if a file is a directory
- Determining if a file is a regular file
- Recursively listing directory contents
- Drawing pixmaps on an XmDrawingArea widget
Berkeley Sockets
- Creating a TCP/IP socket server
- Creating a TCP/IP socket client
- Unblocking a socket
- Waiting for an un-blocked socket to be writeable
- Checking if an un-blocked socket has incoming data
- Getting the IP address of the local machine
Windows 3.X stuff
Determining if a file is a directory
#include <sys/stat.h>
int
is_dirfile(char *path)
{
struct stat s;
if (stat(path, &s) == -1)
return 0;
else if ((s.st_mode & S_IFMT) == S_IFDIR)
return 1;
return 0;
}
Determining if a file is a regular file
#include <sys/stat.h>
int
is_regfile(char *path)
{
struct stat s;
if (stat(path, &s) == -1
|| (s.st_mode & S_IFMT) == S_IFDIR
|| !(s.st_mode & S_IFREG))
return 0;
return 1;
}
Recursively listing directory contents
This example assumes that you have already done a chdir to the base listing directory (ie:
chdir("/usr"); ). When linking this example, you need to be sure to link libc
before libm (-lc -lm)
#include <stdio.h>
#include <dirent.h>
#include <string.h>
static void
recursive_list()
{
DIR *dirp;
struct dirent *direntp;
if ((dirp = opendir( "." )) != NULL)
{
while ((direntp=readdir(dirp)) != NULL)
{
if (is_dirfile(direntp->d_name))
{
/* don't follow . or .. */
if (strcmp(direntp->d_name,".")
&& strcmp(direntp->d_name,".."))
{
printf("%s:\n", direntp->d_name);
/* if we found a directory, change to it & recurse */
if (chdir(direntp->d_name)==0)
{
recursive_list();
chdir("..");
}
}
}
else
{
printf("\t%s\n",direntp->d_name);
}
}
closedir( dirp );
free(direntp);
}
}
Drawing pixmaps on an XmDrawingArea widget
This example assumes that you are using an 8-bit (pseudo color) visual.
void
load_pixmap(Display *dpy, char *filename, Pixmap *p)
{
if (*filename != NULL
&& access(filename,F_OK) == 0)
{
Screen *scr = XDefaultScreenOfDisplay(dpy);
*p = XmGetPixmapByDepth(scr, filename,
XBlackPixelOfScreen(scr),
XWhitePixelOfScreen(scr), 8);
if (*p == XmUNSPECIFIED_PIXMAP)
printf("Unable to load %s\n",filename);
}
else
printf("Unable to locate %s\n",filename);
}
void
draw_pixmap(Display *dpy, Widget dest, GC gc, Pixmap p,
int x, int y, int width, int height)
{
XCopyArea(dpy, p, XtWindow(dest), gc, 0, 0, width, height, x, y);
}
Creating a TCP/IP socket server
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
int sd,sdcur;
struct sockaddr_in sin;
int addrlen;
.
.
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = INADDR_ANY;
sin.sin_port = htons(PORT);
/* get socket */
if ((sd=socket(sin.sin_family, SOCK_STREAM, 0)) == -1)
{
perror("unable to get socket");
exit(1);
}
if (bind(sd, &sin, sizeof(sin)) == -1)
{
perror("unable to bind socket");
exit(1);
}
/* listen for client connections */
if (listen(sd, 5) == -1)
{
perror("listen");
exit(1);
}
/* accept a connection */
sdcur=accept(sd, &cin, &addrlen);
.
.
/* now, talk to client on sdcur using send/recv or read/write */
.
.
close(sdcur);
close(sd); /* close socket, or loop back and accept another connection */
Creating a TCP/IP socket client
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
struct sockaddr_in sin;
struct hostent *hp;
.
.
/* get host entry */
if ((hp=gethostbyname("corwest")) == 0) /* your server name goes here */
{
perror("unable to get host info");
exit(1);
}
memset(&sin, 0, sizeof(sin));
dom_inet.sin_family = AF_INET;
dom_inet.sin_addr.s_addr = ((struct in_addr *)(hp->h_addr))->s_addr;
dom_inet.sin_port = htons(0x9999); /* your port number goes here */
/* get socket */
if ((sd=socket(sin.sin_family, SOCK_STREAM, 0)) == -1)
{
perror("unable to get socket");
exit(1);
}
/* connect to server */
if (connect(sd, &sin, sizeof(sin));
{
/* do your thing here */
}
close(sd);
#include <fcntl.h>
void
unblock_socket(int sd)
{
int flags;
/* get current socket flags */
if ((flags=fcntl(sd, F_GETFL)) == -1)
{
perror("GETFL");
exit(1);
}
/* set socket to non-blocking */
flags |= O_NDELAY;
if (fcntl(sd, F_SETFL, flags) == -1)
{
perror("SETFL");
exit(1);
}
}
Waiting for an un-blocked socket to be writeable
void
waitfor_send_ready(int sd)
{
fd_set wfds;
int response;
do
{
FD_ZERO(&wfds);
FD_SET(sd, &wfds);
if ((response=select(sd+1, NULL, &wfds, NULL, NULL)) == -1)
{
perror("select write");
exit(1);
}
}
while (!(response != 0 && FD_ISSET(sd, &wfds)));
}
Checking if an un-blocked socket has incoming data
int
recv_ready(int sockfd)
{
fd_set rfds;
int response;
FD_ZERO(&rfds);
FD_SET(sockfd, &rfds);
if ((response=select(sockfd+1, &rfds, NULL, NULL, NULL)) == -1)
{
perror("select read");
exit(1);
}
return (response != 0 && FD_ISSET(sockfd, &rfds));
}
Spawning an external app
The following example opens c:\mydoc.txt in notepad (notice that I had to add a space to
the beginning of the command line args to make this work).
struct LOADPARMS {
WORD segEnv;
LPSTR lpszCmdLine;
LPWORD lpwShow, lpwReserved;
};
HINSTANCE hinst;
struct LOADPARMS parms;
WORD awShow[2] = {2,SW_SHOWNORMAL};
parms.lpwReserved=(LPWORD)NULL;
parms.segEnv=0;
parms.lpszCmdLine = (LPSTR)" c:\\mydoc.txt";
parms.lpwShow = (LPWORD)awShow;
hinst = LoadModule((LPSTR)"notepad.exe",&parms);
if ((UINT)hinst < 32)
MessageBox((LPSTR)"Couldn't spawn editor");
Getting the HWND of a spawned app
Assuming you know the instance handle of the spawned app (as in the above example), this
code will get you the window handle...
HWND hwChild;
BOOL CALLBACK GetWins(HWND hWnd, LONG lParam)
{
if ((HINSTANCE)GetWindowWord(hWnd, GWW_HINSTANCE) == (HINSTANCE)LOWORD(lParam))
{
hwChild = hWnd;
return FALSE;
}
return TRUE;
}
HWND HinstToHwnd(HINSTANCE target)
{
WNDENUMPROC lpEnumProc = (WNDENUMPROC)MakeProcInstance((FARPROC)GetWins,
AfxGetApp()->m_hInstance);
hwChild = 0;
EnumWindows(lpEnumProc, MAKELONG(target,0));
FreeProcInstance((FARPROC)lpEnumProc);
return hwChild;
}