diff --git a/genman.sh b/genman.sh
index f33a47b..7ae6bf5 100755
--- a/genman.sh
+++ b/genman.sh
@@ -1,5 +1,6 @@
 #!/bin/bash
 
-cd src && help2man -n "instrumentation CPU profiler" -N -o cpuusage.1 ./cpuusage
+mkdir -p build && cd build && cmake .. && make -s && \
+cd ../src && help2man -n "instrumentation CPU profiler" -N -o cpuusage.1 ./cpuusage
 exit ${?}
 
diff --git a/src/cpuusage b/src/cpuusage
index 6b45522..91ba74a 100755
--- a/src/cpuusage
+++ b/src/cpuusage
@@ -68,9 +68,9 @@ showusage()
 # Version
 showversion()
 {
-  echo "cpuusage v1.20"
+  echo "cpuusage v1.21"
   echo ""
-  echo "Copyright (C) 2017-2018 Kristofer Berggren"
+  echo "Copyright (C) 2017-2020 Kristofer Berggren"
   echo ""
   echo "cpuusage is distributed under the BSD 3-Clause license."
   echo ""
@@ -91,7 +91,7 @@ fi
 
 # Arguments - regular options
 ALL="0"
-AUTO="1"
+MANUAL="0"
 DEBUG="0"
 FUNCS=""
 INCS=""
@@ -135,7 +135,7 @@ while getopts "?acdf:i:j:m:o:p:r:sv" OPT; do
     READ="${OPTARG}"
     ;;
   s)
-    AUTO="0"
+    MANUAL="1"
     ;;
   v)
     VERB="true"
@@ -253,7 +253,7 @@ if [ -f "${TMPDIR}/headers.txt" ] && [ -f "${TMPDIR}/prototypes.txt" ]; then
   ${VERB} && echo "cpuusage: starting program ${1}"
   JSONPATH="${TMPDIR}/cutrace.json"
   if [ "${DEBUG}" == "0" ]; then
-    CU_FILE="${JSONPATH}" CU_AUTO="${AUTO}" \
+    CU_FILE="${JSONPATH}" CU_MANUAL="${MANUAL}" \
       LD_PRELOAD="${TMPDIR}/build/libwrapper.so" \
       DYLD_INSERT_LIBRARIES="${TMPDIR}/build/libwrapper.dylib" \
       DYLD_FORCE_FLAT_NAMESPACE=1 "${@:1}" &
@@ -262,7 +262,7 @@ if [ -f "${TMPDIR}/headers.txt" ] && [ -f "${TMPDIR}/prototypes.txt" ]; then
   else
     LLDBCMDPATH="${TMPDIR}/lldb.cmd"
     echo "env CU_FILE=\"${JSONPATH}\""                                      >  "${LLDBCMDPATH}"
-    echo "env CU_AUTO=\"${AUTO}\""                                          >> "${LLDBCMDPATH}"
+    echo "env CU_MANUAL=\"${MANUAL}\""                                      >> "${LLDBCMDPATH}"
     echo "env LD_PRELOAD=\"${TMPDIR}/build/libwrapper.so\""                 >> "${LLDBCMDPATH}"
     echo "env DYLD_INSERT_LIBRARIES=\"${TMPDIR}/build/libwrapper.dylib\""   >> "${LLDBCMDPATH}"
     echo "env DYLD_FORCE_FLAT_NAMESPACE=1"                                  >> "${LLDBCMDPATH}"
@@ -297,7 +297,7 @@ elif [ -f "${TMPDIR}/nowrappers.txt" ]; then
   ${VERB} && echo "cpuusage: starting program ${1}"
   JSONPATH="${TMPDIR}/cutrace.json"
   if [ "${DEBUG}" == "0" ]; then
-    CU_FILE="${JSONPATH}" CU_AUTO="${AUTO}" \
+    CU_FILE="${JSONPATH}" CU_MANUAL="${MANUAL}" \
       LD_PRELOAD="${LIBDIR}/libcpuusage.so" \
       DYLD_INSERT_LIBRARIES="${LIBDIR}/libcpuusage.dylib" \
       DYLD_FORCE_FLAT_NAMESPACE=1 "${@:1}" &
@@ -306,7 +306,7 @@ elif [ -f "${TMPDIR}/nowrappers.txt" ]; then
   else
     LLDBCMDPATH="${TMPDIR}/lldb.cmd"
     echo "env CU_FILE=\"${JSONPATH}\""                                      >  "${LLDBCMDPATH}"
-    echo "env CU_AUTO=\"${AUTO}\""                                          >> "${LLDBCMDPATH}"
+    echo "env CU_MANUAL=\"${MANUAL}\""                                      >> "${LLDBCMDPATH}"
     echo "env LD_PRELOAD=\"${LIBDIR}/libcpuusage.so\""                      >> "${LLDBCMDPATH}"
     echo "env DYLD_INSERT_LIBRARIES=\"${LIBDIR}/libcpuusage.dylib\""        >> "${LLDBCMDPATH}"
     echo "env DYLD_FORCE_FLAT_NAMESPACE=1"                                  >> "${LLDBCMDPATH}"
diff --git a/src/cpuusage.1 b/src/cpuusage.1
index 9ec80ea..2f7367a 100644
--- a/src/cpuusage.1
+++ b/src/cpuusage.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.8.
-.TH CPUUSAGE "1" "November 2019" "cpuusage v1.20" "User Commands"
+.TH CPUUSAGE "1" "February 2020" "cpuusage v1.21" "User Commands"
 .SH NAME
 cpuusage \- instrumentation CPU profiler
 .SH SYNOPSIS
@@ -103,6 +103,6 @@ Written by Kristofer Berggren
 .SH "REPORTING BUGS"
 Report bugs at https://github.com/d99kris/cpuusage
 .SH COPYRIGHT
-Copyright \(co 2017\-2018 Kristofer Berggren
+Copyright \(co 2017\-2020 Kristofer Berggren
 .PP
 cpuusage is distributed under the BSD 3\-Clause license.
diff --git a/src/cumain.cpp b/src/cumain.cpp
index d77be53..ee8f6e6 100644
--- a/src/cumain.cpp
+++ b/src/cumain.cpp
@@ -61,20 +61,24 @@ static std::string cu_addr_to_symbol(void *addr);
 /* ----------- Global Functions ---------------------------------- */
 void __attribute__ ((constructor)) cu_init(void)
 {
-  char *manual = getenv("CU_AUTO");
+  if (getenv("LD_PRELOAD") == NULL) return;
+  
+  char *manual = getenv("CU_MANUAL");
   if ((manual != NULL) && (strncmp(manual, "1", 1) == 0))
   {
-    cu_start_tracing(0);
+    signal(SIGUSR1, cu_start_tracing);
+    signal(SIGUSR2, cu_stop_tracing);
   }
   else
   {
-    signal(SIGUSR1, cu_start_tracing);
-    signal(SIGUSR2, cu_stop_tracing);
+    cu_start_tracing(0);
   }
 }
 
 void __attribute__ ((destructor)) cu_fini(void)
 {
+  if (getenv("LD_PRELOAD") == NULL) return;
+
   cu_stop_tracing(0);
 }