diff --git a/msvc/config.h b/msvc/config.h
index c476c07..c3ff561 100644
--- a/msvc/config.h
+++ b/msvc/config.h
@@ -35,7 +35,7 @@ typedef unsigned short uint16_t;
 typedef signed char int8_t;
 typedef unsigned char uint8_t;
 
-typedef unsigned long int uintptr_t;
+#include <stddef.h> /* Has uintptr_t etc. */
 typedef int pid_t;
 
 #define inline /* undefined */
diff --git a/src/fuzz.c b/src/fuzz.c
index acd4ebf..3a48386 100644
--- a/src/fuzz.c
+++ b/src/fuzz.c
@@ -115,7 +115,8 @@ void _zz_fuzz(int fd, volatile uint8_t *buf, int64_t len)
     int64_t pos = _zz_getpos(fd);
     struct fuzz *fuzz;
     volatile uint8_t *aligned_buf;
-    int i, j, todo;
+    int64_t i, j;
+    int todo;
 
 #if 0
     debug("fuzz(%i, %lli@%lli)", fd, (long long int)len,
@@ -132,7 +133,7 @@ void _zz_fuzz(int fd, volatile uint8_t *buf, int64_t len)
         /* Cache bitmask array */
         if(fuzz->cur != (int)i)
         {
-            uint32_t chunkseed = (i + (int)(fuzz->ratio * MAGIC1)) ^ MAGIC2;
+            uint32_t chunkseed = ((int)i + (int)(fuzz->ratio * MAGIC1)) ^ MAGIC2;
             _zz_srand(fuzz->seed ^ chunkseed);
 
             memset(fuzz->data, 0, CHUNKBYTES);
@@ -246,8 +247,8 @@ static void readchars(int *table, char const *list)
                      && tmp[1] && strchr(hex, tmp[1])
                      && tmp[2] && strchr(hex, tmp[2]))
             {
-                new = ((strchr(hex, tmp[1]) - hex) & 0xf) << 4;
-                new |= (strchr(hex, tmp[2]) - hex) & 0xf;
+                new = ((int)(strchr(hex, tmp[1]) - hex) & 0xf) << 4;
+                new |= (int)(strchr(hex, tmp[2]) - hex) & 0xf;
                 tmp += 2;
             }
             else
diff --git a/src/libzzuf.h b/src/libzzuf.h
index 53072d9..3824cf7 100644
--- a/src/libzzuf.h
+++ b/src/libzzuf.h
@@ -34,7 +34,7 @@ struct fuzz
 {
     uint32_t seed;
     double ratio;
-    int cur;
+    int64_t cur;
 #ifdef HAVE_FGETLN
     char *tmp;
 #endif
diff --git a/src/mygetopt.c b/src/mygetopt.c
index ed9f696..90408f1 100644
--- a/src/mygetopt.c
+++ b/src/mygetopt.c
@@ -86,7 +86,7 @@ int mygetopt(int argc, char * const _argv[], const char *optstring,
 
         for(i = 0; longopts[i].name; i++)
         {
-            int l = strlen(longopts[i].name);
+            size_t l = strlen(longopts[i].name);
 
             if(strncmp(flag + 2, longopts[i].name, l))
                 continue;
diff --git a/src/zzuf.c b/src/zzuf.c
index 1d3a3f2..59dc522 100644
--- a/src/zzuf.c
+++ b/src/zzuf.c
@@ -428,7 +428,7 @@ static void loop_stdin(struct opts *opts)
             _zz_md5_add(ctx, buf, ret);
         else while(ret)
         {
-            if((nw = write(1, buf + off, (size_t)ret)) < 0)
+            if((nw = write(1, buf + off, (unsigned int)ret)) < 0)
                 break;
             ret -= nw;
             off += nw;
@@ -1032,8 +1032,8 @@ static void *get_entry(char const *name)
         return NULL;
     }
 
-    return (char *)nt->OptionalHeader.ImageBase +
-                           nt->OptionalHeader.AddressOfEntryPoint;
+    return (void *)(uintptr_t)(nt->OptionalHeader.ImageBase +
+                                 nt->OptionalHeader.AddressOfEntryPoint);
 }
 #endif